Importing and Exporting CAD Files

PRO If you’re a SketchUp Pro user, you can import or export CAD files, which use the .dwg or .dxf file formats.

Before you import a file, it’s helpful to know what CAD elements SketchUp Pro does and doesn’t support and how to prepare your CAD file for best results. Then, you can walk through the basic importing steps outlined in this article. After you’re done importing, check out Starting with a CAD File in SketchUp Pro, which offers several tips and tricks for handling imported CAD geometry.

If you’re exporting a SketchUp Pro file to a CAD format, how you import a CAD file depends on whether it’s a 2D file, such as a floor plan, or a 3D model. In this article, you also discover how SketchUp data is exported into CAD format.

Understanding what CAD elements SketchUp can import

Before you import a CAD file into SketchUp, it’s helpful to know what CAD elements SketchUp can and can’t import. Then, you can prepare your CAD file so that you’re able to work with the elements that you need in SketchUp. The following table outlines what CAD elements SketchUp does and doesn’t support. If an element isn’t supported, SketchUp simply ignores it when you import the CAD file.

Preparing a CAD file for import into SketchUp

When you take a few steps to check and prepare your CAD file before import, you can make sure all the data you need imports into SketchUp and streamline the import process. The following sections outline what you need to look for and how to resolve any potential conflicts between CAD elements and SketchUp.

Change unsupported elements

If you need to import unsupported CAD elements into SketchUp, try exploding those elements in CAD so they become primitive CAD drawing elements that SketchUp does support. Here are some examples:

• In Autodesk Architectural Desktop, you can explode ADT walls and extrusions so that they import into SketchUp as faces.
• In AutoCAD, you can explode objects such as doors, windows, stairs, and contour lines. When you explode CAD objects into block entities, they import into SketchUp as components. If you explode the CAD block entities into polylines, the polylines import into SketchUp as lines or polylines.

Delete unnecessary layers

In an imported CAD file, SketchUp automatically discards any entities that have no 3D relevance, such as text, dimensions, hatching, logos, and so on. However, SketchUp won’t discard the layers holding these entities. To avoid a bunch of empty layers in SketchUp, you may want to delete those layers from the CAD file before you import it into SketchUp.

Move geometry close to the origin

In SketchUp, geometry that’s many miles or kilometers away from the origin (0,0) can cause performance problems. To avoid these problems, check the placement of geometry in your CAD file before you import the CAD file into SketchUp.

For example, say you’re importing Autodesk AutoCAD DWG files, such as civil site plans, in order to work with the contour lines. If the graphic or geometry is far away from the origin, move it close to the origin before importing the CAD file into SketchUp.

Alternatively, deselect the Preserve Drawing Origin option in SketchUp’s DWG/DXF import options, as explained in Importing a CAD file into SketchUp, later in this article.

Reduce the file size if needed

Generally, CAD files import into SketchUp successfully when the file size is 15MB or less. When you import larger CAD files, the import can take a long time or may fail. Conversely, the smaller your CAD file size, the quicker and easier the import. Also, after a complex CAD file is imported into SketchUp, you may notice that SketchUp’s performance slows down. That’s because lines and faces in SketchUp contain more data than their CAD equivalents.

Check the unit of measure

If possible, find out the unit of measure used to create the CAD file. When you import the CAD file into SketchUp, you need to know whether your file uses inches, feet, or a metric unit of measurement. That way, you can match the SketchUp model’s units to the CAD file’s units and thus maintain the scale and dimensions of your imported CAD geometry.

In SketchUp 2018 you also have the option to import the model using the units specified in the CAD file. In the Units dropdown, select “Model Units” from the list. This will attempt to match the units saved in the CAD file. If SketchUp is unable to determine what unit of measurement was used to create the CAD file, it will default to 1 CAD unit equals 1 inch in SketchUp.

Save in a SketchUp-compatible CAD file format

When SketchUp imports a CAD file, SketchUp strips the information to its basic geometric components. So no matter what AutoCAD file format you use (such as 2010 or 2007), the end result is essentially the same. To maximize compatibility between a CAD file and SketchUp, however, saving your CAD file in the Release 13 or Release 14 format works best.

Importing a CAD file into SketchUp

After you've checked and prepared your CAD file, you're ready to import it into SketchUp. The following steps walk you through the import process, based on your current operating system:

1. In SketchUp, open the SketchUp model into which you want to import your .dwg or .dxf file.
2. Select File > Import. An Open dialog box appears.
3. Navigate the the place your hard drive where your CAD file is saved.
4. From the Files of Type drop-down list, select AutoCAD Files (*.dwg, *.dxf).
5. Select the file you want to import.
6. Click the Options button. The Import AutoCAD DWG/DXF Options dialog box appears, as shown in the following figure.
7. (Optional) In the Geometry area, select Merge Coplanar Faces to tell SketchUp to automatically remove triangulated lines from planes. Selecting the Orient Faces Consistently box tells SketchUp to analyze the direction of imported faces and orient the faces so that their direction is uniform.
8. (Optional) To import geometry at the correct scale, select the unit used in your CAD file from the Units drop-down list. Your options are Model Units, Inches, Feet, Yards, Miles, Millimeters, Centimeters, Meters and Kilometers.
   Tip: If you don't know the units used in the original file, use a large unit type, such as feet or meters. Then you can resize the model as necessary after it's imported.
   Warning: If you select a small unit, such as millimeters, but the model was originally intended to display in feet, you can unintentionally create itty-bitty faces that will be lost on import. For SketchUp to recognize a face, the face must be .001 square inches or larger.

9. (Optional) Select the Preserve Drawing Origin checkbox to place the imported geometry at the origin defined in the .dwg or .dxf file. Leave the checkbox deselected if you want to place the imported geometry near the SketchUp origin.
10. Click OK in the Import AutoCAD DWG/DXF Options dialog box.
11. Back in the Open dialog box, click Open, and SketchUp Pro begins importing your CAD file.

1. In SketchUp Pro, open the .skp file into which you want to import your .dwg or .dxf file.
2. Select File > Import. An import dialog box appears.
3. Navigate the the place your hard drive where your CAD file is saved.
4. From the Format drop-down list, select AutoCAD Files (*.dwg, *.dxf).
5. Select the file you want to import.
6. Click the Options button. The DWG Import Options dialog box appears, as shown in the following figure.
7. (Optional) To import geometry at the correct scale, select the unit used in your CAD file from the Units drop-down list. Your options are Inches, Feet, Millimeters, Centimeters, and Meters.
   Tip: If you don't know the units used in the original file, use a large unit type, such as feet or meters. Then you can resize the model as necessary after it's imported.
   Warning: If you select a small unit, such as millimeters, but the model was originally intended to display in feet, you can unintentionally create itty-bitty faces that will be lost on import. For SketchUp to recognize a face, the face must be .001 square inches or larger.

8. (Optional) Select the Preserve Drawing Origin checkbox to place the imported geometry at the origin defined in the .dwg or .dxf file. Leave the checkbox deselected if you want to place the imported geometry near the SketchUp origin.
9. (Optional) In the Geometry area, select Merge Coplanar Faces to tell SketchUp to automatically remove triangulated lines from planes. Selecting the Orient Faces Consistently box tells SketchUp to analyze the direction of imported faces and orient the faces so that their direction is uniform.
10. Click OK in the DWG Import Options dialog box.
11. Back in the import dialog box, click Import, and SketchUp Pro begins importing your CAD file.

Understanding how SketchUp data is exported to CAD format

Before you export a SketchUp model to a CAD file format (.dwg or .dxf), you may find it helpful to understand how SketchUp data is translated into the CAD format that you choose. Here’s what you need to know:

• SketchUp faces are exported as a triangulated polyface mesh with interior splframe hidden lines (if applicable). This conversion helps to simulate the appearance of your SketchUp file, even when all exported faces are triangular.
• SketchUp uses the current units set in the Units pane of the Model Info dialog box as a reference for translation to a .dwg or .dxf file. For example, if the current Model Info unit setting is Decimal and Meters, then AutoCAD must be set to decimal for the units to translate correctly as meters when you open the exported file in AutoCAD.
• Duplicate line entities aren’t created on top of a p-line entity.

Exporting a SketchUp Model as a 2D CAD file

When export your model view as a 2D CAD file, you can choose the scale and a number of line options. The result is a 2D vector file in .dwg or .dxf format that you can open in your CAD program.

Follow these steps to export a 2D CAD file:

1. To maintain your model’s scale in the exported file, in SketchUp, select Camera > Parallel Projection. Then set your view to one of SketchUp’s standard views by selecting Camera > Standard Views and selecting an option from the submenu that appears. (See Viewing a Model for details about the model view options.)
2. Select File > Export > 2D Graphic.
3. Navigate to the place where you want to save your exported file.
4. (Optional) Change the file name if you’d like to name the exported file something other than the SketchUp file’s current name.
5. Select either the .dwg or .dxf file type. In Microsoft Windows, select this option from the Export Type drop-down list. On a Mac, use the Format drop-down list.
6. Click the Options button to set the scale and line options, which are explained in detail in the upcoming list. When you’re done, click OK in the DWG/DXF Hidden Line Options dialog box (Microsoft Windows) or the Export Options dialog box (Mac OS X).
7. Click Export and your CAD file is saved in your selected location.

In the following figure, you see the line options dialog box for your current operating system. The following list introduces your options so that the lines in your exported file meet your needs:

• AutoCAD Version: Select what version of AutoCAD you’d like to use to open the exported file.
• Drawing Scale & Size: The Full Scale checkbox is selected by default. However, if you deselect that checkbox, you can set a custom scale. In the In Drawing box, type the actual measurement you want to use to set your scale. In the In Model box, type the value for scaling your exported model. For example, for a scale of 1:4, type 1’ in the In Model box and 4’ in the In Drawing box. To customize the page size, enter values in the Width and Height boxes.
• Profile Lines: Here, you can customize how profile lines appear in your exported file. You can set the line width as follows:
  • Select None to export profile lines at the standard width.
  • Select Polylines with Width to export profile lines as AutoCAD polylines. When you select this option, you can leave Automatic selected so that the exported lines match the profile line width. If you deselect Automatic, you can enter a custom width in the Width box.
  • Select Wide Line Entities to export profile lines as AutoCAD wide line entities.
  
  The Separate on a Layer checkbox, which is selected by default, creates a layer for profile edges. If you’ve used SketchUp layers to control visibility, note that SketchUp layer assignments don’t translate directly when you export a SketchUp file to a 2D CAD file.
• Section Lines: If you export section lines or a section slice, these export options become available. See Slicing a Model to Peer Inside for details about sections and how to export them.
• Edge Extensions: Some CAD applications might have problems recognizing line endpoints and intersections when your model uses SketchUp line extensions. Deselect the Show Extensions checkbox to toggle extensions off in your exported file. If you leave Show Extensions selected and deselect the Automatic checkbox, you can enter an exact length for line extensions in the Length box.

In Microsoft Windows, you can select the Always Prompt for Hidden Line Options if you’d like to set options in this dialog box anytime you export a 2D CAD file. You can also restore the default settings by clicking the Defaults button.

Exporting a SketchUp Model as a 3D CAD file

When you export a SketchUp model as a 3D CAD file, you can select what entities are exported. To export your model, follow these steps:

1. In SketchUp, select File > Export > 3D Model. The Export Model dialog box appears.
2. Navigate to the location where you want to save your exported file.
3. (Optional) Change the file name if you like. By default, the exported file uses the same name as your SketchUp file name.
4. Select either .dwg or .dxf as the file format for your exported file. In Microsoft Windows, select your file type from the Export Type drop-down list. In Mac OS X, use the Format drop-down list.
5. Click the Options button to open the Export Options dialog box, shown in the following figure. From the AutoCAD Version drop-down list, select the version of AutoCAD you’d like to use to open the exported file. In the Export area, select the checkbox for each type of entity that you want to include in the exported file. Click OK when you’re done.
6. Back in the Export Model dialog box, click Export, and your file appears in the location where you chose to save it.