Is it possible for plates, tiles or small pieces ? Is it possible to use MLCAD with a Makerbot replicator?

  • 8
    I can't imagine that the tolerances would be as good as LEGO's - would probably be on a par with MegaBloks ;) Commented Mar 10, 2012 at 13:38
  • 1
    Yes, but the quality would not be that good. See this (my) answer on a related question.
    – fouric
    Commented Mar 27, 2012 at 4:08
  • The MakerBot Replicator 2 produces surfaces with 100 micron precision according to MakerBots website.
    – user1174
    Commented Nov 28, 2012 at 23:21
  • See the referenced answer by InkBlend; precision of normal lego pieces out of box is under 10 microns. The quality you can get from a 100 micron printer is not going to work as well as a real piece. Once we have 10x precision for the 3D printers, things might change. Commented Mar 24, 2014 at 6:51

3 Answers 3


(fair warning: I work for a 3D printer company [Type A Machines])

I thought this cross-posting up on the RepRap forum would be useful here.

Summarizing that post:

It is possible to 3D print LEGO-compatible parts on desktop 3D printers, but with caveats:

  1. The fit will likely never be as tight as real LEGOs. Those are tough tolerances to match. LEGO Corp are (I've heard) the masters of injection molded plastic.

  2. The fit we achieved is not bad though, but to make it work you can't just print the holes at the exact diameter and just hope it works.

  3. I did my models in CAD software and (CRUCIAL POINT) had to expand hole sizes by about 1/2mm to get the right fit.

  4. I added 1mm chamfers to the holes as well.

  5. I also widened the holes after printing with a 4.8mm drill bit. No power tools needed, just a few turns manually.

...but with those caveats, it's totally doable. The holes I printed stuck quite nicely to the top of a standard LEGO 8x8 plate. Of course, it's crazy to try and print any standard LEGO/Technic brick. LEGO corp does that so much better than you ever will. The interesting thing is making custom pieces that you'll never see from LEGO. There are a lot of interesting 3D designs out there that - with the methods above - allow you to turn them into a LEGO component.


LDview can directly export LDraw files to .STL. But the problem is that the mesh obtained may not be suitable for 3D printing, many of LDraw parts are not "watertight", or contain surfaces inside the part volume (eg. studs are simply lain on flat top surface).


You can't directly export from MLCad to the .STL format that the Makerbots require, but there are workflows you could probably set up.

MLCad doesn't really have many export options, so you're better off using something like LeoCAD which can read .ldr files from MLCad, and export as other formats.

  1. Using LeoCAD, add the part you want to print to the scene.
  2. Export as either .3ds or Lightwave .obj, and import into Blender.
  3. Export from Blender as an .stl file (native exporter).
  4. Open the .STL in ReplicatorG and away you go.
  • 1
    I've heard there are limitations to printing layer-by-layer as parts can be very brittle. How do home-made bricks compare to the real thing, is it even a viable option?
    – Ambo100
    Commented Mar 10, 2012 at 15:44
  • Good question - I really doubt that the precision of the printers are anywhere close to actual LEGO bricks. Commented Mar 10, 2012 at 19:57

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