In many countries, the DWG format is still widely used in the building industry. Therefore, the ability to create DWG files with high standards of quality is an important requirement. This is of particular importance if national standards have to be supported, but this may also apply for company standards.

General Documentation Note: This Revit DWG Standard tool was created in response to needs of the Austrian Government CAD standard ÖNORM 6241-1, but this utility can be used for any national or corporate CAD standard.

This document will reference the Austrian standard as an example standard to explain the software functionality. The management of dwg template files, block attributes and geometric fidelity are essential for compliance with any CAD/BIM deliverable; because of this the Austrian standard will serve as an effective example for other CAD standards in this document.

It should also be noted that the Layer-Standard “AIA”, which is widely used in the US, is also used as a reference, and an example configuration using the AIA Standard is also shipped with the tool.

General Approach

The creation of DWG files is a standard feature built into Revit. The feature does not provide a mechanism to allow an application to modify the functionality, as it is possible for the IFC export. There are a number of ways to configure the functionality of the DWG export, but apart from this, the feature can only be used the way it is implemented, therefore the DWG Export built into Revit does not allow to support the creation of DWG files according to a specific CAD Standard.

With the „Enhanced DWG Exporter for Revit“, CAD Anwendungen Muigg provides a tool that offers the functionality that has been requested by the community of Revit users and offers basic Export-Configurations to support Standards. The tool has been developed to provide a maximum of flexibility. This means that the user can create and modify configurations which support national or company standards which can be used and shared using a network.

Revit can create DWG files for any kind of views, but Enhanced DWG Exporter for Revit (EDER-Tool) it is primarily focused on the creation

of floor plans.

Individual Pieces of Functionality

The picture below shows the various options that can be used as graphical symbols:

Allow the use of “Drawing Templates” for the DWG Export

Revit does not allow to define a “template drawing” for the export. But this is a standard procedure for AutoCAD user. In order to make sure that a drawing does comply with an existing standard, a drawing is usually “inserted” into an empty drawing created from a template. This makes sure that the definition of blocks and layers is as defined by the template, rather than using the definitions found in the “external” drawing.

Allowing users to create a drawing that is created from a template also helps to resolve a number of problems in conjunction with the existing DWG export functionality of Revit, e.g. the use of a “STB” plot configuration.

Creation of Tag Blocks with Attributes instead of Text Elements

In the Austrian Standard “ÖNORM 6240-4” it is a requirement that a “room tag” does have a specific name and the naming of the attributes is also specified. Space tags are only one example for an annotation family; they can be used for many purposes. It is possible to either assign a specific tag block with defined attributes using a mapping table controlling which Revit parameter shall be assigned to which attribute or to use an “automatic mode” where the name of the block will correspond to the name of the annotation family and its attributes are named according to the parameter name.

Creation of Attributes which are Part of a Family

This functionality is similar as for annotations as described above. But this new piece of functionality also allows to convert the text originating from a tag which is part of a user defined family into an attribute of the block that represents the family symbol. In addition to that it is also possible to create attributes from parameters which are not displayed as tags. These attributes are created as invisible attributes. This way it is possible to export the complete parametric information contained in the Revit parameters to a DWG file.

Special Post-Processing Options for Doors and Windows

As the Standard “ÖNORM A 6240-4” is one of the standards to be supported, this special piece of functionality is necessary.

These are the specific processing options for doors and windows:

- Creation of a special annotation tag (axis-annotation)

- Creation of a polyline around the boundary of the opening.

The annotation tag for a door or a window can either be an additional annotation or part of the definition of the door/window family. The functionality described above for other annotation.

The purpose of creating a polyline is to specify the position of the door/window.

Providing a more Comprehensive Functionality for the Layer-Assignment

Revit only allows the assignment of layers on a per category basis. But if, for example, a piece of bathroom furniture has been modelled as “General Model” it is not possible to “override” the layer assignment so that this element is exported to another layer. This additional functionality is provided by this tool. Such “overrides” can be created for any family / type.

Assigning Material Information for Walls

Another option is to create layers containing information about the material of the walls. This is only possible if the layer standard used does include a mechanism to store material information in layers.

Use of Parameter Values to control the Layer

For Revit 2018, the features do define layer standards have been enhanced considerably. It is now possible to define layer-components which are only used for certain categories and it is now also possible to use the value of a parameter attached to an element to control the value of the layer or a layer component. So, for example, the parameter “Structural” can be used to control the layer value where the wall will be exported to.

Use of Shared Coordinates for the DWG Export also for Drawing Sheets

For Views, it was already possible to use shared coordinates for the exported DWG. This means that the DWG files are “geo-referenced” and use a coordinate system “East-West”, “North-South” and the correct north orientation as defined in Revit. The release for Revit 2018 of the Enhanced DWG Exporter for Revit now contains an extension that allows to create geo-referenced drawings from drawing sheets.

Identify Islands and Cutouts in Spaces

Revit does allow the export of spaces as polylines. However, no distinction is made between the space boundary and cutouts inside a space, both polylines are exported to the same layer. During the post-processing of the DWG file this this can be achieved and the layer for islands or cutouts will be modified.

Management of Layer Assignments

The option to restore layer assignments from a file is no longer available in the current versions of Revit. Using the API, it is still possible to read and write the layer mappings, and this is being used in order to manage different layer assignments. It is also possible to create the layer assignment from a named export setting and to modify and manage it with this utility.

The Enhanced DWG Exporter for Revit stores configurations either local or on a network, so it is possible to share configurations with other users.

Creation of Spaces from DWG Files Adhering to a Standard

If a DWG file contains spaces which are defined by polylines and a space tag which is defined by a certain standard it is possible to create spaces in Revit from this information. In order to do that, a “mapping table” is required to tell Revit how to assign the information contained in the attributes of a space-tag block to the parameters of a space. This is the same information which is also required to export a Revit model into a DWG file, i.e. this mapping table should already be available.

Management of Configurations

All the options mentioned in the previous chapters can be combined independently from each other in a “configuration setting”. This can also be combined with a certain export configuration setting for Revit which contains additional settings with regards to font files, hatch patterns and other settings which are not explicitly dealt with in the EDER Tool.

All the settings are stored and managed in external files. The last setting used as well as a number of other settings are stored in the system registry and will be automatically set when the command is invoked.

Installation

Important:

As it is necessary to create entries in the system registry during the installation, administrator rights are required to run the installation.

The Enhanced DWG Exporter for Revit uses RealDWG , this is an Autodesk product to create and modify DWG files. RealDWG is already installed with Revit, only a few additional components are required and are included with the Enhanced DWG Exporter for Revit.

Storage Location for the Configuration Information

The data which is required for a configuration should be stored in a location, where users with standard privileges have write access in order to be able to modify the configuration. Unlimited access for a user without administrator rights is only available in folders, which are directly assigned to a user. Therefore, this information is stored in this location:

C:\Users\<User>\AppData\Roaming\Autodesk\Revit\RevitToDWG

Whereas <User> has to be substituted with the current user. This folder cannot directly be seen in the Windows Explorer, but this should not be a problem because the files stored there should not be manipulated directly by the user.

In addition to this folder, 3 additional folders will be created underneath the folder mentioned above:

Block_DWGS

Configurations

LayerStandards

These folders contain template DWG’s and blocks for the pre-installed configurations, the folder “Layer-Standards” is used to define layer standards which are used in different configurations.

When the executable containing the tool is started by clicking on it, the installer will first check if the tool is installed for the first time. If this is the case, the destination folder can be selected:

Installation oft he Tool

The installation is started by clicking on the executable containing the installation, the name of this file is:

RevitToDWGSetup_2018_ENU_V4.exe

The name “RevitToDWG” is the “internal code name” for the tool, the file name contains the Revit Version, the release number and the language for the installation and documentation. The tool itself currently supports 3 Languages:

· English

· German

· French

The only information to be provided is the folder where the tool shall be installed.

When the installation is complete, you can use the button “Show details” and the following screen will be displayed:

If Autodesk CAD and BIM Standard Tool for Revit has already been installed before, the dialogs described before will not be displayed, but the information about where to install it will be taken from the registry, the application will be installed in the same location and only the shown above screen will be displayed.

One of the files which will be created during the installation is a so called „.addin“ file for Revit. This file contains information regarding addins and will automatically be read the next time Revit is launched, and when you select the button “AddOns”, the following buttons will be displayed – besides any other add-ons already installed – the button with the DWG Logo and another button for the creation of spaces will be displayed:

Using the Enhanced DWG Exporter for Revit

The functions of the tool will be displayed when you activate the “Add-Ins” menu:

The picture above shows the 2 buttons for the tool. In order to run it, click on the button with the DWG icon:

The information displayed in the upper right corner of the dialog under

Variable / Optional components for the current export

is dependent on the currently active layer standard and may also be missing altogether, more on this will be documented later in this document.

In order to export the current view according to the configuration which is displayed in the “list of available configurations”, all you need to do is to press the button “Start Export”.

After that, the DWG export built into Revit will be processed, which can be seen in the progress-dialog on the lower left side of the screen, and then a “Progress-Dialog” will be displayed with information about the step which is currently processed.

Managing Configurations

In order to modify an existing configuration, you need to press this button:

In the upper portion of this dialog, the postprocessing options which shall be used for this configuration can be selected by activating the appropriate checkbox. The meaning of the symbols is:

Layer Assignment

Definition of Layer-Overrides

Post-Processing options for Blocks created from Family symbols

Assignment of material-information for walls and layers of walls

Post processing for annotations

Post processing for doors and windows.

In order to modify the configuration of these options, you need to press the button “Detailed Configuration” which will display this screen:

The individual configuration of this options will be discussed later.

In the lower part of the dialog, more options for the configuration are shown as “picture buttons”, the meaning of the symbols is:

Creation and management of a layer-standard

General Options

Settings for the template drawing

Setting the path for the configuration files

As the assignment of layers for the Revit elements is a key piece of functionality, the definition of a “Layer-Standard” is of particular importance.

A key feature of the “Enhanced DWG Exporter for Revit” is the ability to define “Layer-Standards” which specify the structure of a layer name. Therefore, this feature is described first.

Creation and Management of Layer-Standards

This function is activated with this button, clicking it will display this dialog:

The list on the top of the dialog contains all the layer-standards which are currently available. Pressing the button “Edit” will display the Dialog wo define ore modify a layer standard. In order to rename a layer standard, you need to enter a new name in the text-box “Rename Layer Standard” and the press the appropriate button. The button “New” will create a new empty layer-standard and with “Copy” you can save the current standard under a new name. The button “Delete” is used to delete a layer standard.

The actual process to create and modify a layer-standard will be described in the next chapter.

Please note: Changing the layer-standard which is assigned to an export configuration may result in a loss of information concerning the layer-assignments contained in the current configuration because these layer-definitions use the structure defined in the layer standard that has been used previously. Because of this, the following dialog is displayed:

You have to decide if you want to keep the existing layer assignments or to delete them – or to undo the change of the layer-standard. Selecting option1 (keep the existing assignments) only makes sense when the structure of the new layer-standard is the same as for the original one.

General Options

This button will display this dialog:

The following aspects of the tool can be configured

Settings for the export of spaces
Default Settings for Annotation-Families/Blocks
Settings for the Revit export configuration
Settings for the export of drawing sheets
Settings for the drawing unit and the AutoCAD version of the exported DWG files

Settings for the Export of Spaces

In order for the post processing to work, the checkbox “Export Spaces as Polylines” has to be checked. In addition to that, the layer and color on which these space polylines shall be put has to be defined. The layer for cutouts has also to be specified. As Revit does not distinguish between the space boundary and a cutout, this distinction will be done during post processing the drawing.

Use of a Revit Export Configuration

Revit allows the creation of named Export-Configurations .

These basically include all export settings. Some of these settings are overridden by the Enhanced DWG Exporter for Revit functionality, such as Layer Mapping.

However, there are a number of settings that are not covered by the Enhanced DWG Exporter for Revit, such as the assignment of font files and hatching. To avoid having to "duplicate" these settings in Enhanced DWG Exporter for Revit, you have the possibility to specify the name of the export device in a configuration.

This Export configuration will then automatically be used set for the export, if it is available in the current model. If an export configuration does not exist when exporting a drawing, the export can still be performed.

Default Settings for Annotation-Families/Blocks

The option to create blocks with attributes out of annotation families is an important feature of this tool. As it is possible to create AutoCAD layouts out of “sheets” in Revit, the need to be able to use standard title blocks in layout drawings has arisen. As these title blocks may have different graphical entities (boxes, lines, logos) as the corresponding “title block” in Revit, it is now possible to use the graphics defined in AutoCAD instead of the Graphics in Revit. The values of the attributes in AutoCAD Block shall obtain the corresponding information of the parameters of the “ProjectInfo” element in Revit by providing a “mapping” between the parameters and the attributes. In order to achieve this additional functionality, two additional “flags” had to be provided, the default value for these flags can be set in the “General Options” page, whereas the actual value for a particular assignment of an annotation family to a bloc has to be made on the Property-Page “Annotation Families”.

The options are:

· Remove Revit Graphics

· Use Attribute Position of AutoCAD Block

In order to achieve that for a title block (or any other annotation) the graphical elements from Revit are removed and the positions of the attributes are taken from the block definition in AutoCAD (rather than the position of the tags in Revit), both checkboxes have to activated.

In addition to that it has to be specified, what do of an annotation tag displaying the value of a Revit parameter has not been “mapped” to an attribute of the corresponding AutoCAD block.

There are 4 possible settings:

· Add to existing block

· Create additional block

· Keep as Text

· Delete

If attributes from tags, which have not been assigned, are added to the block anyway (which is possible programmatically), the result is, that the block contains attributes which cannot be found in the block definition. This situation has been declared inacceptable by some standards like the Austrian Standard. If the second Option is chosen, the result is that an additional block is created with all the tags that have not been mapped are added to this additional block. The name of this extra block will obtain its name by appending a postfix to it like “ROOM_TITLE_Z01“, the block contains only attributes and ist insertion point is the same as for the standard-block.

The third option is to leave the block as text, i.e. it is not converted to a block attribute, and the forth option is to remove these tags altogether.

Settings for the Export of Drawing Sheets

When the current view is a drawing sheet, the different views in the sheet can be exported as XREF’s, this is controlled by he setting of the corresponding checkbox in the dialog.

It is also possible to use “shared coordinates” for the export of DWG files. When a view is exported, the position defined in the Revit model (North/South and East/West coordinates and the orientation relative to the north direction) can be used to create a drawing which is “geo-referenced”. For the export of drawing-sheets, this is not supported by the standard DWG export built into Revit. Using the Enhanced DWG Exporter for Revit does allow the creation of geo-refenced drawings also for the export of drawing sheets.

Note: The creation of geo-refenced DWG files for sheets is only possible, when the option to create XREF’s is active and when a drawing-template is used!

Configuration of a “Drawing Template”

Using a template drawing (.dwt file) makes sense for 2 reasons. First, it is assumed that all the blocks with attributes used for annotations are defined within this drawing. The second reason to use a template is, that when using a template, the following process will in invoked during the export:

- A copy of the template drawing will be created

- The drawing created by Revit will be inserted into this drawing.

So, technically, as a result of this, all the settings concerning layers, colors, line-types etc. will be used the way it is defined in the template drawing, and not as it is defined in Revit. Another effect will be that standard layouts etc. will be in the resulting drawing, just as it happens when an AutoCAD drawing is created from a template.

The path of the template drawing is displayed in the text-box and using the button “Select …” a different one can be selected. It also can be defined, which drawing unit shall be used when exporting the drawing.

Since release 2016, it is also possible to post-process drawing sheets, therefore it is possible to select, which „Layout“ of the template drawing shall be used, of if the Layout created automatically by Revit („Layout1“) shall be used.

Define the storage location of the configuration files

The standard location for the storage of the configuration files is:

C:\Users\<User-Name>\AppData\Roaming\Autodesk\Revit\RevitToDWG

This path is only accessible to the current user. If several users want to work with the same configurations, the location for the configuration files has to be changed by selecting a different directory which typically will reside on a network drive.

Copy the current configuration

With the button „Export current configuration data …“ the current configuration can be copied to another directory. All the files and directories located inside the folder RevitToDWG will be copied, including the folder RevitToDWG , this folder name is pre-assigned and has to be present.

Defining another storage location

First you need to select “ Custom Location” , in order to activate the button „ Select a folder for the configuration data“. With this button, another directory can be selected, e.g. the one previously created with the export feature described above.

The folder selected must be named „ RevitToDWG“ , it will also be checked if the folders LayerStandards , Configurations and Block_DWG “ do exist, and if not, an appropriate message will be displayed.

After another directory has been selected, the dialog will automatically be closed in order to re-initialize the content due to the new configuration files.

Export of the Configuration Files

With this button you can export the current configuration files to another folder without changing the current storage location.

Creation and Management of Layer-Standards

A layer standard is independent from a certain “export configuration” of the Autodesk CAD and BIM Standard Tool for Revit, because it is possible to use a certain layer standard for any number of such export configurations. Therefore, the layer standards are stored independently from configurations.

The intention of the Autodesk CAD and BIM Standard Tool for Revit is to be able to define any layer standard. But the goal is not to “define” a layer standard as such, but to view a layer standard from the perspective of Revit. The aim is to use as much information as possible which is available from the Revit model and map it in a more or less automatic fashion to a particular layer standard.

Layer-Mappings for complex Layer-Standards

Many layer standards which are in use for national and international standards, but also by individual companies, do assume that there is no simple “one to one” mapping between a certain object type and a certain layer. The Austrian standard, for example, allows it to store the phase status (existing, new, and demolished) in a layer, the scale and the projection mode (floor plan, section, perspective view etc.) and also the material used in the name of a layer at a certain position of the layer name. The requirement to provide the information about the material of a wall in a layer could not be achieved by a simple mapping mechanism.

In order to provide functionality of this kind, the concept of a “layer context” has been developed. This means that different components of a layer standard are classified in a way that either an automatic mapping to particular information from within the Revit model is possible, or if the assignment has to be provided manually by the user.

For the components which can be assigned automatically, a mapping between the Revit model and a code from the layer standard can be provided.

Creation of a Layer-Standard without Structure

It is an important feature of this tool, to use layers which have a “structure” and to assign layers in an easy an efficient way – and in an automatic fashion whenever possible. But it should also be noted that it is possible to create a “layer-standard” that does not have any structure. Such a layer-standard would, for example, consist of only one component with variable length named “Name”. This is possible, but it is not recommended!

General Considerations for the Definition of a Layer-Standard

As it is now possible to define layer-standards which have different components depending on the category, it should be possible to define layer-standards which are not completely “homogenous”. In many cases, the structure of the layer name for annotations is different as for model categories. Using the option to define components which are only valid for a certain category or category-type, this problem can now be resolved. Therefore, the procedure to “model” a certain layer-standard with the tool, should be:

· Find out, how many different “structures” there are

· Find common properties for these different structures

This way it should be possible to find common features which are applicable to all categories, and then the components which apply to a certain category of category type can be identified.

The option to define components of a layer-standard which are only valid for certain categories, now allows to define “partitions”. This is a term used in set theory. A partition on a set is a collection of subsets that do not have any elements in common, and the union of all the partitions is the complete set. An example for a “partition” according to the definition above would be the set of even numbers and the set of odd numbers as subsets of the set of natural numbers.

It could also be, that the layers for some categories are completely unstructured, and this situation can also be modeled. If, for example, layers for annotations have a completely different structure as layers for model elements, it is possible to form a “partition” as described above:

Component 1: Annotation-Layer, Valid only for categories of type “Annotation”

Component 2: Modell-Layer, Valid only for category types „Model“ and „Analytic“

As any category must be contained in one of the 3 category-types available, the 2 components cannot “overlap”.

Definition / Modification of a Layer Standard

The dialog for the creation and modification of a layer-standard can be displayed by pressing the button:

and then as well as activating the button „Edit“ button in the dialog for layer-standards:

For the purpose of this documentation, the Layer-Standard “ÖNORM A 6240-4 Engl” (which is the Austrian Standard partly translated into English) will be used in most situations. The functionality also covers the AIA layer standard used in the United States, a few features in the mechanism to describe layer standards had to be implemented especially in order to support the AIA standard and in order to explain these features the AIA standard will be used as an example.

The dialog below displays the definition of the layer-standard A-6240-4:

The rows describe one individual component, the meaning of the columns is:

Name of the Component
Length (in number of characters)
Fixed length (yes or no)
Separation character (variable) or default character (fixed)
Optional (yes or no)
May be missing (yes or no)
Context for the component
Possible values
Button for the mapping table
All categories (yes or no)
Button for the selection of categories
Button for the definition of the parameter

It should be noted, that the in the columns for buttons, these are displayed only if the definition of the component requires it. For example, the button to define the category for which a component is used will only be displayed, if the checkbox “All categories” is unchecked.

The buttons on the lower left of the dialog are used to insert a line above or below the current line, to delete a line od to append a line at the end.

Decomposition of the Layer Standard into Components

Main Group	Responsibility	Content		Representation
Subdivision		Group	Detail	1. Char	2. Char
Character-Nr	1-2	3-4	5-8	9	10

As the picture above shows, some components grouped together into higher level parts. Therefore, the question has to be answered if it makes sense to decompose the components or if the higher level group shall be used when describing the layer standard. In this example shown above, the component “Responsibility”, “Content” and “Representation2 could be used to describe the standard, or if the components should be broken down to “Group”, “Detail”, “1. Char” and “2. Char”.

In this example, it was necessary to break the standard down to the “smaller” components, because the list of possible values is only given at this level, and not for the level “Content”.

In general it is recommended, to break down a standard into components as detailed as possible. If the layer structure is defined by a national standard, there is also a list of “allowed values” for the various component. Therefore it is necessary to define these components individually.

Components with Fixed or Variable Length

As the picture above shows, the layer standard ÖNORM A6240-4 uses only components with fixed length, i.e. every character within a layer name has a specific meaning.

For a standard using components with fixed length, the character defined as “delimiter” stands for “not specified, in the case of the Standard shown above, this character is the minus-sign “-“, and this means, that the value for this group is not specified. If a standard uses components with variable length, the field “length” specifies the maximum length allowed for a component. The AIA Standard does have both components with fixed length as well as with variable length, the definition of the AIA Standard is shown below:

The component “Discipline” can either have 1 or 2 characters, so there is no fixed length for this component but a variable length with a maximum of 2 characters in length, and a “delimiter” character “-“ so that it is possible to find the end of the component designator.

But there are also standards which use variable length, in this case it is necessary to define “separation characters” and this character must not be used within that component.

It is possible to combine components with fixed length and components with variable length in a standard, for example the standard used by AutoCAD Architecture uses an “Originator” as first character followed by 2 components with variable length separated by the “Underline” character (“_”).

Optional Components

Optional Components are those which are not mandatory. In many cases there will be an agreement between a contractor and an architect which components of a standard shall be used. If a component is defined as “Optional”, it has to be specified on export time if this component shall be included or not and all the optional components will be shown on the Export dialog:

On the upper right part of the dialog, all the optional components of the layer standard currently used are listed and by using the checkboxes the components can be activated or not. If, for example, all the optional components shown above will be unchecked, the length of the layers will be 10 characters, when all components are used, the length will be 20 characters.

Defining Components which are only Applicable for Certain Categories

Since the version of the tool for Revit 2018 it is possible to define such components. This makes the definition of layer-standards more comprehensive.

The category or categories which are valid for a component can be specified in several ways:

· Using the “category-type” (Model, Annotation, Analytic)

· By selecting individual categories

· By exclusion of individual categories

Components of a layer that may be missing

In the AIA standard there are 2 components “Minor Group 1” and “Minor Group 2” which can be specified for a particular layer or not. The difference to “optional” components is that these if it is decided that an optional component shall be used, it has to be present for every layer in the drawing, whereas components that may be missing can be used in one layer and missing in another layer. It is necessary that these components can clearly be identified in a particular layer, therefore it is necessary that these components have a fixed length and a delimiter which can be thought of as a “prefix” to a particular component. If a component that may be missing is used as last component of a layer standard, it is also allowed to use components with variable length.

In the AIA Layer standard, all of the following layers are valid:

A-WALL

A-WALL-FULL

A-WALL-FULL-TEXT

The Component “Major Group” has to be specified for every layer, but the components “Minor Group 1” and “Minor Group 2” can be used or not. The actual value of the minor group codes are “FULL” and “TEXT”, the “-“ character is used to separate the components and can be seen as a “prefix” to the minor groups.

With the option to define components which are only used by certain categories it should no longe be necessary to use this option, as components, which are only used for certain categories can be defined accordingly. This is usually better than to use the option “may be missing”.

The “Context” of a Layer Component

There are 9

different assignments

User defined per category
User defined per category and representation
Used defined per Export
Projection
Scale
Status
Material
Constant field
Parameter-driven

The “context” which is assigned to a component determines how the mapping from the Revit model to a layer – or rather a layer component – is made.

A component is either “user defined” (as the first 3 types of context in the list above) or it is “automatic”. Automatic means, that the value for the component can be assigned automatically based on information available from the model, as, for example, the scale of a view, the material or the value of a parameter.

It is obvious that the decision if an automatic context can be used depends on how well structured a layer-standard is. It seems obvious that it makes a lot of sense to use automatic components wherever possible because these do not have to be assigned manually.

The different values for the “Context” are now described.

User Defined per Category

For this type of context, the assignment of the component for a category is manual.

It should be mentioned again that it is possible to define components which are only valid for certain categories (and also sub-categories).

User Defined per Category and Representation

This special context has been introduced because it allows for a distinction in the assignment of a model category to a layer depending on whether the element is being “cut” or if it is seen as a projection.

In Revit, a floor plan is actually considered as a horizontal section at a certain elevation, and as edges resulting from “cutting through” the element are displayed in a different color or line type, a distinction is made between “Projection” and “Section”. If a standard does allow the representation of projections and sections using different layers or colors, this context shall be used.

Using this context will have the following effect in the layer assignment dialog:

In the specification of the layer for a “Section” you can see, that only those components which use the context “User defined per Category and Representation” can be set individually for “Section” and “Projection”, the other components are “grayed out” which means these components will have the same setting for a “Projection” and for a “Section”.

User Defined per Export

The difference between “User defined per Category” and “User Defined per Export” is, that a component which is “User Defined per Category” can be pre-defined using a mapping table, and this is not the case for a component defined “User Defined per Export”. For example, a layer in the ÖNORM standard may contain information about the planning phase, but this cannot automatically be “mapped” to a certain kind of information available from the model, there is no such thing as “built-In planning phases” in Revit, therefore this information must be provided by the user before starting the Export.

Projection

This information is available for every view in Revit, therefore an automatic mapping is possible.

The values for views which can be exported to AutoCAD are:

Floor plan
Ceiling Plan
Elevation
3D View
Section
Engineering Plan
Area Schema
Section
Detail
Undefined

These values can be assigned to the appropriate code in the layer standard.

Scale

The scale is also stored for every view. Any scale can be used, but only these values can be automatically assigned:

1:1
1:2
1:10
1:20
1:50
1:100
1:200
1:500
1:1000
1:2000
1:5000
User Defined

Status

This corresponds to the “phases” in Revit. The following assignments are possible:

Existing
Demolished
New

It has to be noted that this context has been introduced originally for the sake of completeness, but it has not yet been fully implemented.

Material

In Revit there is a “Material-Class” which can be used to create an overall classification for every material. The values for the “Material-Class” are not predefined, but can vary in a model file. It is, however, assumed that in a company, some kind of standardization of the materials will be consistent. The assignment to a code from a layer standard can only be made on a “Material Class” basis, not every individual material, more on that will be discussed in the section “Walls”.

Constant Field

Constant fields can, for example, be used as a “delimiter”. In the ÖNORM standard, for example, it is possible that users expand the layer names past the 20 characters. But if a user choses to do so, a certain delimiter has to be used first in order to clearly indicate this intention.

The Context „Parameter-driven“

This context works like the “layer overrides” in the standard DWG Export function in Revit. A major advantage in terms of usability is, that the value of a parameter can be used to control only one component layer name, whereas in the standard Revit export it is necessary to specify the full layer name and the composition of it manually for every category.

In addition to that, there are also a few more functional extensions as compared to the standard layer-override feature in Reit:

· Every parameter can be used, not only a few predefined ones like “Structural”

· It is also possible to use type-parameters

· For the definition of mapping tables it is possible to use ranges uf values, not only single values

Possible Values for a Layer Component

This information specifies, what the content of this component is or what it can be. The possible settings are:

Fixed list of values
Free text
A constant value
Context-List

If a “Fixed list of values” is specified for the allowed values, a button will be displayed besides the dropdown list for the value settings. When this button is activated, a dialog will be displayed to enter or modify the values for the list.

Defining the Values for a Component

The dialog shown displays the codes and the description for the list for the component “Discipline” in the AIA Standard.

It is also possible to read the values for the layer components from a DWG file or from an export-configuration in Revit by pressing the button “Import values”. This will display the dialog shown below:

The component names can either be read from an export-configuration in Revit of from a DWG file. All the layers will be read and the names will be broken down into components in order to create a list of possible values.

It is, however, not possible to obtain a description of a component, this can be added later manually.

Definition of “Context-Lists”

The option “Context-List” is similar to “fixed value lists”. But for certain standards the components are defined in a way that sub-components provide a more detailed description for the higher level component. The German car make Porsche, for example, uses a layer-standard with 3 components

· Main-Group

· Sub-Group

· Detail

The values for the sub-group are different depending on the main group. For standards of this type, this type of value list definition has been implemented. In the process of defining a layer for a particular category, the change of the value of the “main-group” component will automatically result in reloading the values of the “sub-group” for that particular value of the main-group component. The dialog to capture the values for a “context list” for the “Porsche” layer standard looks like this:

In order to add a value, the appropriate value of the “governing component” must be selected first.

It is possible to import values as described above.

For a constant value, only one value can be entered.

Creation / Modification of Mappings with Automatic Components

In earlier versions of the tool it was possible to define the context „User Defined by Category“ as an automatic context, but this has lead to misunderstandings and is no longer supported and the corresponding checkbox has been removed.

For all components with automatic contexts, a button for a mapping table will be displayed and can be used to define the mapping between the values from the layer standard and the internal Revit information.

This is shown for the mapping for the scale of a view:

On the left side of the dialog you can see the values as defined in the layer-standard, and on the right side you see the values available in Revit.

When a line is selected on the left side, it will be displayed what is currently assigned and this can be modified by clicking on the checkbox.

Defining the Category / Categories for a Layer Component

hen a category is created, the "All Categories" flag is automatically set, that is, this component applies to all categories. If this is not the case, this checkbox must be deactivated, then a "button" with the text "..." will be displayed in the corresponding line, which can then be used to define for which categories and subcategories a component applies. Clicking it will display this dialog:

In the area at the top left, you define how the categories for this component should be defined:

· • Define by category type(s)

· • Selection of individual categories

With the option "category type" is selected, the lower area of the dialog is deactivated, only the selection of the category type is possible. When selecting individual categories, the "Model", "Annotation" and "Analytical" checkboxes are also important because only the categories of the category type that have been activated are displayed.

There are two options when using the " Selection of individual categories " option:

· • Include selected categories

· • Exclude selected categories (filter is taken into account)

These two options make it possible to define "complementary components" (e.g., "partitions"), e.g. a component applies to walls and columns, and the "complementary" component to all other components except walls and columns.

Note: For components that have the context “parameter-driven”, only the option "Specify individual categories" and "Include selected categories" option may be used to define the category. This is because there are normally no parameters that are used by all categories when "category types" are used or when the option “exclude categories” is used.

Specifying Sub-Categories for a Layer Component

It is also possible to define components of a layer standard which only apply to certain sub-categories. To do this, you first have to select the category for which the sub-categories shall be defined, as shown below:

In this example, the component shall only be used for the sub-category “Cut-Pattern” for walls. How the selection of sub-categories shall be dealt with is controlled by 4 radio-buttons:

· For all elements

· Only for elements with the sub-category selected

· Elements without sub-category + elements with selected sub-category

· Elements without sub-category except elements with selected sub-category

When „All elements“ is selected, the selection for sub-categories is deactivated and a specification of sub-categories is not possible

It has to be noted that not all elements have a sub-category assigned, so this case must be dealt with. Similar to the categories, a sub-category selection can also be made via "exclusion", i.e. you can define components that only apply to certain subcategories and those that apply to all subcategories except those that have been selected.

However, it is only necessary to define subcategories in exceptional cases, but it is possible to differentiate between them, since this is also possible with the Revit Layer overrides - which should become obsolete due to the availability of the context "parameter-driven".

Define the Parameter for the Context "Parameter-driven"

If the setting "Parameter-driven" is used for a context, a button is displayed in the last column of the layer standard dialog with which the parameter to be used can be selected. The dialog for this is shown below :

In the line at the top of the dialog, the name of the current component for which a parameter is to be defined, and if a parameter is already defined, the name of it is displayed. Since determining the list of parameters requires that the current model is "searched" for elements of the selected categories and this process takes some time, this is not executed immediately, but only when the "Start finding the parameters" is pressed. You can specify whether both type and instance parameters are to be determined, or only one of these 2 types of parameters. If several categories have been selected, the checkbox " Display only parameters available in all categories" controls which parameters are displayed. The checkbox is initially checked, otherwise the situation may occur that a parameter is not defined for some categories. If "Include parameters from annotations" has been selected for a component, it can be controlled whether the parameters specific for annotations (such as "Leader") should be displayed, which is usually not useful.

In the upper left part of the dialog, the following options can be selected:

· Use the value of the parameter for the layer

· Use a mapping table

If the second option is selected, a "mapping table" must also be defined, which will be described later. However, it is also possible to directly use a parameter value. You could, for example, define a parameter called "Layer" for the "Walls" category, and the value of this parameter would then contain the name of the layer or the layer component.

When the "Start parameter determination" button is pressed, the parameters are displayed:

If a parameter has already been set, it is selected. The line shows the type of parameters (built - in, family, project parameters) and whether it is a shared parameter. It also shows the data type of a parameter. To select a parameter, press the leftmost column to select the entire row.

Defining Mapping Tables

The function of the assignment table depends on the data type of the parameter. In the case of "Yes / No" values, there are obviously only 2 possible values known in advance, "True" and "False", so these two values are entered in the rightmost column (if not already assigned) the "Find parameter values" button below the list of values is deactivated.

In order to use a value from the list, press the button „Copy value / interval“, the value will then be copied and the name of the layer component can be entered – in this case the value to be used for structural walls.

With the button „Add value / interval”, this entry will be added to the list, and after repeating these steps for non-structural walls, this is what the dialog will look like:

However, it is also possible to create a mapping table for parameters that have a real number as a data type. For example, in the case of rooms, a layer component could be defined which has a specific value depending on the area of the room. If you now press the button "Determine parameter values" after opening the parameter dialog, the list of parameter values is displayed:

Now you can also specify a mapping for "intervals", e.g. for rooms with 10 - 20 m², the value for "Status" should be "A" and for rooms between 10 and 20 the value should be “B”.

There is a special kind of parameters that use a "list of values". These are stored internally as an integer, but a certain number has a fixed meaning, an example of this kind of parameter is the parameter "Function":

The internal value for specific "function" is indicated in brackets, as shown above, and with "Copy value / interval", only the numeric value is used.

Please note! Only the values that are actually used within the model will be displayed.

Example of a Layer-Standard with a „Parameter-driven“ Context

In the layer standard ÖNORM A-6240-4, the second component of the layer standard is the "group" (the first component is the "responsibility"). Examples of values of the "group" are:

BS	Fire safety
BT	Operational
DA	Roofs
DB	Recesses
DE	Ceilings

In the case of walls, however, the load-bearing function "WT" for supporting and "WN" for non supporting walls is also specified in the component “Group”.

Many layer standards provide the possibility to map the load-bearing function of walls in the layer. In order to be able to implement these options, it was necessary to access Revit "layer overrides”. With the availability of the "parameter context", this requirement can now be implemented in a very elegant way, in combination with the option to define components which apply only to specific categories. This will now be explained in detail for the layer standard ÖNORM A 6240-4 used as example.

In order to make this possible, the layer standard used as an example can now be used as follows

The "Group" component is defined twice:

· Group

· Group-Wall

For the "Group-Wall" component, the "context" parameter-driven is selected. Now you have to define the categories for the two components "Group" and "Group-Wall", but first you have to specify that both components do not apply to all categories

And then, the category / categories for which these components are used has to be defined:

Defining the categories for „Group”:

Categories are all except walls. Note that all category types are activated; otherwise, it would only apply to model categories.

And for the component "Group-Wall" the assignment is:

The next step is the definition of the parameter to be used for the component “Group-Wall”:

It is the parameter „Structural”. Finally, the mappings for the values of this parameter (true or false) have to be defined:

This now defines a layer standard that will automatically write the structural function of walls into the layer name.

Configuration of the Various Options for the Post-Processing of the DWG file

The modification of settings is done by pressing the button

In the Export-Dialog. This will display this dialog to activate the options:

And by pressing the button „Detailed Configuration“, the tabs for the various options will be displayed:

General Layer-Assignments

It has to be observed, that the display in this dialog is dependent on the layer standard which is currently selected for the current configuration. If, for example, the currently active layer standard only has on component, the dialog would look like this:

And for a complex layer standard like the AIA standard, more lines will be displayed:

Generally, first the category for which the layer shall be defined has to be selected in the tree dialog on the left side, and then the layers which are currently assigned will be displayed.

For every component of the layer that has a context “User defined by Category” and which is not automatically assigned and for those components with a context “User defined by category and representation” one line will be displayed. Depending on if the component has a fixed list of values of a free text; either a textbox or a scroll down list will be displayed.

The layer for both “projection” and “section” has to be defined. The resulting layer name will be composed from the selections made and is shown in the bottom line labelled “Layer”. Components which will be assigned automatically or for a particular export will be assigned later, for every position a “?” sign will be shown.

Components with the context “User defined by category and representation” will be shown in the section part of the dialog in such a way, that only these components can be modified individually, the other components will automatically be modified when the settings in the section “projection” are changed. If all the components are “User defined per category”, only the color can be modified in the “section” part of the dialog as shown below:

Between “Projection” and “Section” there are buttons so that the settings from “Projection” can be copied to “Section”, either for a single component of for all, when the button besides the text “Section” is used.

The settings will only affect the category / sub category which is currently selected. If a main category is active, the settings can be applied to all the sub categories by pressing the button “Copy settings to all subcategories”.

The button “Expand All” can be used to expand all the nodes.

Layers Overrides

After activating this tab, the current model will be analyzed and all families / types found in it will be shown in the tree dialog grouped by category.

The background for the implementation of this functionality has been mentioned in the beginning of this documentation, it is to have the option to be able to export families to another layer as compared to the one which would normally be used due to the category to which the family belongs. This process can also be thought of as creating an “override”.

Basically, every type or every family (depending on the “level” where the assignment is made, which is either a family or a type, can be exported to any layer.

If a family type is selected, the original category is displayed, and it is possible to select any other category, which will result in displaying the layer which is currently assigned to the category selected. But it is also possible to directly modify the layer without selecting a category first. When the button “Create assignment” is pressed, the layers can be modified and these settings will be saved and stored permanently when the “Apply” button is pressed. If an override has already been created previously for a particular family / type this can also be removed by pressing the button “Remove assignment”.

In previous versions of the tool, other options like renaming the block or using an AutoCAD block could be defined on this page. All of these options are still available but have been moved to a separate tab called " Block Substitution / Attributes ", which is described next.

Block Substitution / Attributes

The following postprocessing operations can be configured on this page:

· Rename blocks created from user-defined families

· Generate block attributes from labels that are part of the family definition

· Replace the block generated by Revit with a predefined block

· Create invisible attributes for individual parameters of an element

As with the "layer overrides", the family or a type for which a postprocessing is to be carried out must first be selected.

Block Options

One of the 3 options can be selected as a radio button

· Lave block name unchanged

· Rename block

· Substitute block from template drawing

The 3^rd option is only displayed if a type has been selected; a block cannot be substituted for a family.

If the "Rename block" option is activated, the individual options are activated:

· Generate block name automatically

· Use predefined name

The name of the block can be generated automatically from the name of the family and type as well as a consecutive number. If you do not select the option "#", there is the risk that the same AutoCAD block will be used for blocks that do not look the same, because in Revit it is also possible to change the geometry by specifying parameters in a family, i.e. 2 types can also look different.

If a block is to be renamed during postprocessing and there is already a new block with this name, it is simply used. If not, the current block is renamed to the new name. The "#" option causes a new block to be generated for each family symbol, e.g. "Single_Flush_800 x 2100_001" for the first, ".._ 002" for the next and so on.

When using the option “Substitute Block from template drawing” is used, you should be aware of the fact that the appearance of the block may change. This option is also available only if a default drawing is used and the list will contains these blocks, otherwise the list is empty.

It is also possible to perform a transformation for a given block when the insertion point of the block is different from the reference point of the family. The dialog can be activated via the "Configure" button, which is activated when the "Transform Block" checkbox is activated.

Dialog to define a translation, rotation, or scaling of a block.

Options to Create Attributes

This options can be found on the right side of the ”Block Substitution / Attributes tab, it contains 2 Checkboxes that can be activated:

· Create attributes from tags

· Additional attributes from parameters

Create Attributes from Tags

When the Checkbox for this Option is aktivated, one of the following Options can be selected:

· Use attributes from selected block

· Automatic name for all attributes

· Use attributes from this block

The first option is only active when the block is substituted by an AutoCAD block. The "Automatic name for all attributes" option causes the attribute to be automatically named after the parameter whose value is displayed in the text. This "automatic" function works only for tags which represent the value of a single parameter. If a label is composed of several parameters, the parameter cannot be determined and the Attribute is named "UNKNOWNx"

The last option "Use attributes from this block" requires a block is selected from the list of blocks. This option allows to define one "attribute block" whose attributes can be used for several families.

Definition of Tag -> Attribute Assignments

If the "automatic" option is not used, an assignment between tags and attributes must be defined in order to assign a certain parameter to an attribute. If no such assignment file exists yet, the question is asked whether it should be created. The mapping dialog looks like this:

On the left is the list of parameters and the right the list of attribute names. Composite labels can also be used, but the tag cannot use more than two parameters.

Create Additional Attributes from Parameters

These attributes are created as invisible attributes and are appended to the block. In this case, an assignment is mandatory. The attributes of the selected attribute block are displayed on the right side and it is also possible to define the name of an attribute automatically according to the parameter whose value it represents:

Material Assignments for Walls

This option only makes sense when the layer standard used allows specifying the material in the layer. There are 2 options available:

Put all layers of a wall on one layer
Assign every wall layer according to its material

Use of the “Material Class”

Usually a large number of materials are used in Revit, therefore the implementation has been made in a way that an assignment is not made to a material, but to a material class which can be defined for any material. So, for example, all the different types of concrete can be assigned to one material class “Concrete”. But this implementation also makes it necessary to have the material class assignments made properly; otherwise it will not be possible to assign the materials to a particular layer.

Assignment of Wall-Types to a Material

In Revit, the material for walls is defined on a per layer basis; a wall does not have a material assignment (unless it consists of only one layer).

But still it is possible to determine the material of a wall by looking at the layer which is defined as “structural” or, if no layer has that attribute, by finding the layer with the maximum thickness.

All the wall types in a drawing it will be analyzed and the result will be displayed in the left part of the dialog.

For some walls, no assignment can be found, in this case, not material will be show. In order to make an assignment, the material can be selected manually, and this will be stored for later use. This mechanism also allows to “override” a material for a wall, so that a wall with a structural layer with the material “Concrete”, it can be assigned a material “Reinforced Concrete” and this assignment has priority.

Assignment of Material-Classes to the Layer Codes

This assignment has to be made for both options (with or without layers). The dropdown list for the “Material Classes” contains all the material classes found in the current project, right to it there are the codes of the current layer standards. All the assignments which have already been made will be displayed.

For the layer by layer assignment, only this mapping is relevant. So it is important that all the materials are properly assigned to material classes and the classes are assigned to the layer codes.

Annotation Families

When Revit exports an annotation family, the result will be a number of individual MTEXT entities for the parameter values. The main reason why a post processing the annotation makes sense is to convert the MTEXT entities to attributes of an annotation tag. These tags have the advantage, that all annotations belonging to a particular annotation family will be grouped together, and in addition to that, an attribute does not only have a value but also a “tag” making it possible to automatically “identify” this information and use it for an attribute extraction, for example.

There are 2 basic settings:

Use an “Automatic Mode” for all Annotations
Use of specific mappings to blocks and attributes

The advantage of the “Automatic Mode” is that all annotation families will automatically be post processed without having to create any additional configurations.

How the Automatic Assignment of Blocks and Attributes Works

In this mode, the attributes are named according to the Parameter which is used in an annotation tag. If, however, a tag contains of more than one parameter (with or without separation string) it is not possible, to find the corresponding parameter, the tag of these attributes will then be „UNKNOWNx“ (x is a consecutive number). In any case, all the attributes will be attached to one block. If an annotation also contains graphical elements (a box, for example) then a block containing this graphical information will be created during the export and all the attributes will be attached to this block.

If no block is created (because there is no additional graphical information), a block named reflecting the name of the annotation family and the name of the type will be created.

Assigning Blocks and Attributes for Annotation Families

In order to create an assignment for an annotation family, the checkbox “Active” in the corresponding line has to be set, and a block must be selected from the list of blocks found in the template drawing.

When this has been done, the line has to be selected, and then the attributes will be read from the block. It will also be checked, if an assignment for this category has already been created. If no assignment file can be found, a question is asked if an assignment file for this annotation category shall be created, otherwise the existing file will be read and the assignments will be displayed.

In order to create additional assignments parameter->attribute, the parameter to be assigned has to be selected from the dropdown list and an attribute has to be selected. It is also possible to have annotations with 2 parameters which are “concatenated”. In this case, both parameters and a separation character have to be selected. The parameters in the list have a prefix to distinguish between “type” and “instance” parameters.

It is also possible to select the flag “Auto”. In this case, no block needs to be selected and an assignment parameters->attribute is not necessary, the mechanism is as described before for the “Automatic Mode”. So it is possible to mix the types of assignments. But if all annotations shall be converted to blocks without a special assignment, the “Automatic Mode” shall be selected.

In addition to that, it can be defined what to do with the graphical information an annotation family may have, and if the position of the tags shall be taken from the original position in Revit or if the position of a corresponding AutoCAD attribute shall be used. It also can be defined what to do, if a tag has been found which has not been mapped to an AutoCAD block attribute. A more detailed description of these options can be found in chapter “General Options” for the configuration under the header “Default Settings for Annotation Families / Blocks.

Post Processing for Doors and Windows

General Remarks

This option is only required if a special annotation for doors and windows has to be created, as it is required in Austria. This annotation is also called “Axis Annotation”. It has to be observed, that the annotation blocks have to be different for the various orientations and the opening sides. In the case of the ÖNORM, these blocks end with the string

„_RECHTS“, „_LINKS“, „_OBEN“ und „_UNTEN“ standing for right, left, top and bottom.

Configuration of the Annotation Blocks

Similar as described in the topic “Annotation Families”, a mapping between the parameters and the attributes of the block have to be provided. This can be done independently for both types of openings by setting the radio button after the text “Currently displayed settings for” To either “Door” or “Window”.

As the axis annotation can also be displayed in a different unit as the unit for the project, the unit used has to be selected

(M or CM) too. It is also possible, that annotations use 2 consecutive parameters, as described in the previous chapter.

Using Annotations as Part of a Family vs. Additional Annotation Tags

Both variants are in use. It has to be observed, that when using additional annotation tags, not all the parameters are available, but only shared or “built-in” parameters. If an annotation tag is used, the name of the family used must also be specified. This way it is possible to create a block for the annotation, but the axis annotation will be created taking care of the orientation.

Creating Polylines for Doors and Windows

This is a special requirement by the Austrian Standard. A polyline has to be created “around” the extent of the opening on a special layer which has to be specified.

Import / Export / Delete and Rename Configurations

This function was created, amongst other things, to be able to create configurations for the tool externally. These configurations can then be exchanged using a ZIP file.

On the Export dialog, this function can be activated via the button shown above. The following dialog is displayed:

To be able to export or import, you first have to select the directory from which you want to export or import, which is done with the button "Select Directory"

After that, all the individual configurations contained in the selected directory will be displayed:

Note: The name of the directory must always be "ReviToDWG" and the corresponding directory structure must exist.

Depending on whether a configuration has been selected from the list on the right or left, the button for import or export is activated and the selected configuration can be exported or imported.

With this dialog, configurations can also be renamed and deleted.

Creation of new Export Configurations

This is done with this button in the Export dialog, this dialog is displayed:

The 3 Options to create a new configuration are:

· Create a new configuration from the current Export-Settings

· Create a new configuration as copy of an existing one

· Create a new configuration with empty layer assignments

Create a New Export Configuration from a Revit Export Configuration

Export facilities of Revit already contain assignments for layers, and these assignments can be captured with this option. Revit does not use any layer standards, it always assigns the entire layer name to a category and this layer name has no "structure" and knows no "components". However, it has to be noted that Revit internally uses the structure of the layer standard used widely in America, the AIA (American Institute for Architects) layer standards.

Therefore, before transferring a configuration from an export configuration, the structure of the layer assignments contained therein should be analyzed and, if necessary, a corresponding layer standard should be created so that the layer assignments can be interpreted correctly. Please also take a look the chapter on layer standards regarding this topic.

Create a Layer-Standard as a Copy of an Existing One

This works similar to „Save As“ to create a „Variant“ of an existing Layer-Standard.

Create a New Empty Layer-Standard

A new Layer-Standard is created with certain default settings, like the use of the layer standard that has previously been active as the layer standard for the new configuration.

By activating the checkbox in the bottom of the dialog, the newly created configuration can be set to be the current configuration.

Running the DWG Export

The view/sheet exported is always the current view/sheet. The name of the DWG file is automatically created according to the current setting, more on this below. The name of the DWG file to be created can also be changed "manually" if required. The export is the directory specified in the group "DWG" Export. With the button

the directory can be changed.

Modifying the Layer Settings for the Export

When the currently selected layer standard has components which are “user defined per export” or if there are components which are optional, these components will be displayed in the Export-Dialog and can be changed if needed.

Automatic creation of the DWG name

With the button "Creation of automatic name" at the lower left end of the dialog, you can configure how the automatic name is to be determined. The following dialog is displayed:

The name can be composed of 4 components, each separated by a configurable separator. These components are:

· Name of the Revit model

· Plan number (only for sheets)

· View name

· Value of a text parameter of the current view

The name of the Revit model is the "rvt" file, without file extension. The "Plan number" component is only available for plans, and the View name is the name of the view or sheet.

Use a parameter of the view / plan for the drawing name

This option was also introduced in version 2018. Some tools allow you to compose the name of the DWG file using a formula or tool. If so, all other components should be disabled and then selected from the list of parameters that contain the name of the DWG file shown in the dialog below

Creation of Spaces from a DWG File

A prerequisite to use this feature is, that the drawing from which the spaces are to be created contains information according to a predefined standard. This does not have to be a national or international standard, it can be any company standard. In AutoCAD, spaces are usually represented as polylines and blocks with attributes. The blocks used as “space tags” need to have a predefined name, and also the attributes tags used in the blocks have to be defined. The assignment of a space tag to a space polyline is done geometrically by specifying that the insertion point of the space tag must be within the space polyline. It also has to be observed that if a space has islands or cutouts, the insertion point of the space tag must not be inside a cutout or island, if not, the space will be assigned to the cutout.

It is also necessary that the layer for the polylines defining the space boundary is different to the layer for cutouts. The name of these layers are specified on the tag “General Options” in the section “Export of Spaces”.

In this example, the Layer „ARRARAID-G“ is used for space boundaries and „ARRARAIN-G“ for cutouts. Depending on the layer standard, the layer can be expanded at the end, so a “filter” will be defined by adding an “*” at the end of the layer name so that not a specific name will be tested, but a name starting with this text.

In addition to that, in the tab “Annotation Families” a block for space annotations has to be defined, and the parameter->attribute assignments have to be specified.

Using this information it is possible to obtain the values for the space name, floor, usage etc. from the AutoCAD drawing.

The space geometry will be created using room separators as straight segments or arcs.

Using the Command

The command is invoked with the button “Create Spaces” from the group „BIM DWG Standard Tool“.

First it will be checked, if the current configuration fulfills the requirements mentioned before. If not, a message will be displayed and the command cannot be executed, i.e. the button “Run Import” will not be activated.

It will also be checked, if the current Revit model does have DWG files attached to it as “CAD Link”, i.e. it must be a external reference which have been created with the command Insert->Link CAD. All the references found will be listed and if it is more than one, a selection has to be made by activating the corresponding line.

The checkbox “Create spaces with tags” controls if a space tag shall be created as well. If this checkbox has been set, all the annotation families for spaces found in the current mode will be displayed, and one type has to be selected, and if this selection has been made, the button “Run Import” will be activated.

For the information created with the spaces it is irrelevant if a space tag is created or which type. The information will be created according to the assignments between attributes and parameters.

The drawing will be analyzed and it will first be checked if the layers and the block definition for the space tag can be found in the drawing, if not an appropriate message will be displayed.

After that, all the polylines and space tags are collected and the assignment of tags to polylines will be done by checking the insertion point of the block. For all spaces found, a corresponding space will be created and displayed in Revit.

At the end, a message telling how many spaces have been created will be displayed.

Note:

It may happen that a message is displayed concerning “inaccuracies of room separators”, which may be displayed. In most cases, this message does not indicate a problem but is due to certain accuracy settings in Revit.