Which resolution is necessary to print bricks with a 3D printer? I would like to print LEGO compatible figures. Which resolution is required for the 3D print in order to firmly fix the figures on LEGO bricks?
Depends on your tolerance. :)


  In the manufacture of LEGO bricks the machine tolerance is as small as
  10 my (0.01 mm).


Source: Company Profile. An introduction to the LEGO Group (2010)

For me, 3D printing resolution would need to be pretty close to that.