Set Linetypes for DWG/DXF Export

In CAD applications, linetypes determine the particular dash-dot sequence, the relative lengths of dashes and blank spaces, and the characteristics of any included text or shapes in lines.

In Revit, these properties are defined as line patterns, which are specified in the object styles assigned to element categories. These patterns can be overridden for a selected element in a specific view.

On the Lines tab of the Modify DWG/DXF Export Setup dialog (see Exporting to DWG or DXF), you can specify the linetype scale that will control how Revit linetype definitions are exported. You can also map Revit line patterns to specific DWG/DXF linetypes as needed.

Setting the Linetype Scale

In AutoCAD, the PSLTSCALE parameter controls paper space linetype scaling. A value of 0 indicates no special linetype scaling. Linetype dash lengths are based on the drawing units of the space (model or paper) in which the objects were created. A value of 1 indicates that viewport scaling governs linetype scaling.

In Revit, the Linetype Scaling setting changes the default behavior of the exported DWG files. Some lines that you would expect to be dashed may now appear solid or in a different scale in either Model or Sheet View in AutoCAD. Regardless of the option you choose, the DWG linetype definitions are created so that a dashed line always begins and ends with a dash.

You can select any of the following options to control the LTSCALE and PSLTSCALE settings in AutoCAD and to control how linetype definitions are exported from Revit:

• Scaled Linetype definitions. This option preserves graphical intent by exporting linetypes the same as they were previously scaled by view scale.
• Modelspace (PSLTSCALE = 0). This option sets the LTSCALE parameter to view scale and the PSLTSCALE to 0.
• Paperspace (PSLTSCALE = 1). This option sets the value of both LTSCALE and PSLTSCALE to 1. Revit linetype definitions are scaled to reflect project units, but otherwise they are exported as is.

Mapping Revit Line Patterns to DWG/DXF Linetypes

By default, all the Revit line patterns listed in the mapping table will have a corresponding DWG linetype generated automatically upon export. This linetype will match the Revit line pattern. If you want to map a line pattern to a specific DWG linetype from the currently loaded .lin file, do the following:

1. Verify that the text box above the mapping table (Load DWG linetypes from) displays the name of the .lin file containing the desired linetype. (To load a different file, click , select a file in the Load Linetypes dialog, and click OK.)
2. In the Linetypes in DWG column, click the value for the pattern, and then select the desired linetype from the drop-down list.

You can click Reset All to change all the linetype values in the table back to {Automatically generate linetype}. Alternatively, you can multi-select rows and click {Automatically generate linetype}.

Note: In cases where a selected linetype contains special segment definitions that cannot be validated by Revit, a linetype will be generated automatically, and the exported element may not display as expected.