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Gavin Grant/3 min read

Controlling Line Weights of Imported CAD Files in Revit: A Step-by-Step Guide

CAD Line Weight Checklist

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This Revit tutorial walks through controlling line weights of imported cad files in revit, covering essential tools and techniques for your projects.

In this video, we're going to look at a way to control line weights of imported CAD files. In the Insert tab of the ribbon, on the right-hand corner of the Import panel, there's the dialog launcher icon, which is a small diagonal arrow at the bottom right corner. Click on that, and it will open an Import Line Weights dialog box.

This dialog box references a mapping file, which is a.txt file located somewhere on your local drive, and it basically maps the 255 possible import colors and assigns each a line weight value. If you scroll down this list, you'll notice it goes all the way to 255. Each of these colors imported from the CAD file is assigned a line weight. Several mapping files are included with Revit, and you can use those or create your own based on your office's CAD standards. Since many existing CAD drawings use colors to determine their line weights when plotted, Revit assigns line weights to the imported elements based on the values input into this table.

Note that if your imported entities use the line weight property rather than color, the settings in this dialog will be ignored, and the assigned line weight will be used instead. If you have access to AutoCAD or another CAD program, it's best to open the files and clean them up in their original environment first. Be sure each detail uses consistent colors and line weight settings to ensure predictable import results.

Delete any unwanted geometry and purge unneeded layers and settings before importing. We're going to import another CAD file, but before we do, let's change some of the line weight values in this table and see how it automatically updates the line weights in the file we're about to import. Let's change color number 3 to value 2, color 4 to 3, and the line weight for color number 5 to 5. Click OK, and if it says you can't write the import line weights file because it's read-only, click Save As, save it in the location of your project, and click Save.

Now, click OK. Be sure you've downloaded the file detail-gip-board-hanger.dwg and saved it in the same folder as your Revit project file. Go to the View tab in the ribbon, and under Create, create a drafting view named "Gypsum Board Ceiling Detail" with a scale of 3 inches equals 1 foot, then click OK.

Now, go to the Insert tab, select Import CAD, browse to where your downloaded files are, and select detail-gip-board-ceiling. Select Open. It may take a moment to load.

Once loading is complete, type "zx" for zoom extents. You'll notice the gypsum board ceiling detail has been imported, and if you zoom in, you’ll see varying line weights based on the settings we just established. If you select the imported file, remember you can use the Query tool in the ribbon. Selecting any line will show the layer it was assigned to; the color assigned to that layer determines the line weight imported. Select the text at the bottom—you'll notice it's on the "Depth Points" layer. Choosing "Hide in View" will hide the Depth Points layer.

In the next video, we'll look at manually assigning callouts to drafting views.