SketchUp to Microstation (via OBJ)

12-4-2008-4-03-53-pmSKP -> OBJ -> DGN

NOTE: This workflow used SketchUp 6 and Bentley Architecture XM.  Subsequent versions of either application may have better (or worse) performance using native SKP (h/t to SF).

There may be situations during the design process where importing SketchUp models into Microstation is necessary. For example, you may want to search Google’s 3D Warehouse for context buildings that you can reference into your Bentley Architecture model for a context rendering of the site. The best way to go from SketchUp to Microstation is through .OBJ. OBJ is the Lightwave file format and seems to be very material/texture friendly. Microstation has no trouble digesting the SketchUp assigned materials and importing them if the correct settings are applied. Follow the directions below to get (most, if not all) of the correct textures and scale.

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Begin by opening the SketchUp file in SketchUp or importing it from GoogleEarth or 3DWarehouse. Make sure all the materials are correctly applied before you export.

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Go to File -> Export -> 3DModel.

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Select .OBJ from the Export Format dropdown. Once this is selected, give the file a name and place it in a convenient folder. NOTE: SketchUp exports the texture maps into a separate folder that must be collocated with the .OBJ file during import. After you have given the file a name and selected a folder to export to, click the “Options” button. In the OBJ Export Options dialog, uncheck all the Geometry options, check “Export texture Maps” and check “Swap YZ coordinates.” Click “OK.” Then click “Export.”

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SketchUp displays a friendly OBJ Exports Results page. Click OK. Fire up Bentley Architecture/Microstation…

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Create a new 3D model file holder (give it an appropriate name) from the 3D-Seed.dgn seed. You will Open the .OBJ into this file. Your first instinct will probably be to “Import” the file, since you “Exported” it from SketchUp. However, Microstation can Open .OBJ files…which is nice.

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Open the .OBJ file in the empty .DGN file.

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If all goes well, you should see your model appear in the viewport. You may need to rotate in order for the textures to appear on the surfaces. You may also need to change the active viewport settings to a shaded render mode.

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Save As a .DGN. It is important to remember that even the DGN file needs to be able to “see” the relevant textures in order for this process to work.  However, once these textures/materials are in the correct location, you can reference your new .DGN from another master file. Simply repeat this process for each relevant context building and you can easily leverage SketchUp models in your BIM workflow where appropriate. Best of luck.

3 thoughts

  1. Why would you go through this process when you can attach the Native SKP file as a reference and then “Merge Into Master”?

    You’re workflow is a good one for SketchUp 7, but for 6 and earlier, I have found it better to just reference and then merge.

  2. SF-

    I’ve yet to test this process using both SketchUp 7 AND V8i, but for SketchUp 6 and XM, I’ve found that the native SKP imports aren’t what they are cracked up to be. The main issue I have encountered is materials. For some reason, SketchUp materials don’t come through into Microstation as they well in SKP format as they do in OBJ. It’s looking like this may have changed in V8i (I’ve yet to test it – anyone out there currently using V8i?) and it will be a welcome improvement. Additionally, I’m happy .3DS support will be there, as that is usually the best backup for interoperability.

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