Recently I created a complex LEGO model with Lego Digital Designer and wanted to import the resulting model into Blender. My export files were missing the LEGO Mindstorms EV3-components that I had added.

The reason for this behaviour are the missing parts in the ldraw.xml-File, which is in the same directory as the ldd.exe, the directory C:\Program Files (x86)\LEGO Company\LEGO Digital Designer held this file for me.

The ldraw.xml is essentially a mapping file, which maps all the LEGO-internal structures to the more open „LDRAW“-File format. The EV3-parts weren’t listed and even in updated ldraw.xml-Files, which I could find on the web, these were never added.

So I created the missing mappings on my own and the result works pretty good. Not all the colours are correct, but I couldn’t find an easy way to correct these.

Here are the necessary steps to successfully export LEGO EV3-parts from Lego Digital Designer and import these with correct colours e.g. into Blender:

1. Copy ldraw.xml file to your location of ldd.exe, overwrite the old ldraw.xml. (Unzip the ldraw.zip to ldraw.xml first)
2. Export your model from Lego Digital Designer to „LDraw-Files (*.ldr)“-format.
3. Open the file in notepad++, search for the following part numbers (they are located at the end of the line) and change the BEGINNING of the line from „1 71“ to „1 15“.
   • Example:
     • 1 71 -90.175277709960937 -176.40634155273437 -275.99981689453125 0 1.0000001192092896 0 0 0 1.0000001192092896 1.0000001192092896 0 0 95658.dat
     • 1 15 -90.175277709960937 -176.40634155273437 -275.99981689453125 0 1.0000001192092896 0 0 0 1.0000001192092896 1.0000001192092896 0 0 95658.dat
   • Do this for all lines with these part numbers (not all might be in your file, only if you have added the corresponding EV3-bricks):
     • 95650.DAT
     • 95658.DAT
     • 95648.DAT
     • 99455.DAT
4. Import the corrected file in LeoCAD and export into „Wavefront (.obj)“
5. Open Blender and follow these instructions to get a first decent result:
   1. File -> Import -> Wavefront (.obj)
   2. Select -> Select all by Type -> Mesh
   3. Press „s“ (SCALE) and enter a value (blind, there is no dialog box), e.g. „0.1“ and hit return. Or you resize with your mouse after pressing „s“.
   4. Right-click and hold on the camera in blender, and move it around to where you want it to be.
   5. Check your current view by hitting the „0“ on your numpad. (This will change to the camera view)
   6. Right-Click during camera view on the border of the camera (it will turn orange), and then right-click and hold outside the camera view to tilt for your needs.
   7. Add some lights via Add -> Lamp -> Area  (or Sun) and position them.
   8. Render by pressing F12
   9. In the render-menu on the right hand side you can change the size of the resulting image, e.g. „Preset: HDTV 1080p“.
   10. By pressing F3 the rendered image is stored to your disc. (Current used path is at the bottom of the render-menu, defaults to /tmp.)