It is easy and stress-free to attach a frame to a large motor in a vertical or horizontal manner as shown in the picture in real life. But I can't do the vertical version inside LDD. Anyone knows why? enter image description here

Is it be because the cross-section of the beam of the frame is not a mathematically perfect square? But I can actually do the following test model in LDD. The yellow and red technic beams have different orientations. The picture is a snapshot of four views of the same test model in LDD. (LDD did close by itself without any message/trace several times when I try creating the model! Very frustrating!) enter image description here

I created a vehicle with a frame attached vertically to a motor. I like to document the process. Can anyone suggest a way to get around the 'restriction'?

The two parts are 95658 and 64179.


1 Answer 1


I slid the Technic frame over an axle instead of a pin to see how far it would go. As shown in the picture below, it appears as if the part is too big to fit all the way because the rim (shown level with the red line) is too thick.

LDD runs a basic collision detection to ensure that no parts overlap. In real life, certain combinations of parts are impossible without stressing the bricks.

The combination of EV3 Motor and Technic Frame in real life have a very, very small amount of friction, so it shouldn't be harmful. But LDD has no tolerance for overlapping parts.

enter image description here

You do have several options:

  • Edit the LXFML file. This is the most technical soloution. Export the LDD file as a .lxfml file as opposed to the standard .lxf. Using a text editor on your computer (such as notepad) you can directly adjust the co-ordinates of the pieces to overlap. However, If you do move the parts apart, you will need to manually put them back together by editing the file. You can find more about LXFML here.
  • Different Parts. Use different parts that perform the same function as the Technic beam, or don't include the part at all.
  • Other Software. You may find it easier to build your model in other LEGO CAD software packages such as lDraw. It should be possible to export your model as it is now and import it into most LEGO CAD applications.
  • Thanks for the explanation. Following your idea, I tried to attach the frame via an offset along an axis, and found the problem you described. I tried to play with various ways to attach the frames, but LDD keep crashing. I re-installed LDD twice, same story, super frustrating! I exported the model and imported into LDraw & LeoCAD. But the EV3, large motors, tires, rims, power joint & ball are all gone.
    – ShungChing
    Aug 30, 2015 at 22:56
  • I want to see if the restriction is artificial on LDD's part, so I tried to build a 3D lattice grid of frames (like a cage) enclosing the motor by orienting the frames in all 3 principal directions, but LDD keep crashing. I want to see the geometry allows attaching the frames in various principal orientations.
    – ShungChing
    Aug 30, 2015 at 23:05

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