LEGO Duplo bricks

It is very hard to make printable perfect fit LEGO bricks.

Here is my version of brick made in FreeCAD.

These parts are NOT classic (small) LEGO bricks compatible!
I did some research about printable Duplo brick with LEGO compatibility with sad results. It needs nozzle 0.3mm and less. All parts are very fragile.

Tested on my printer with 0.4-0.5mm nozzle, 0.20-0.25layer height and sliced by Slic3r v1.1.7 & 1.3.0.

Large bricks are ready to ABS print with measured 100,6% shrinkage.

2x2 & 4x2 Duplo bricks has easy separable supports for small LEGO brick compatibility. It depends on your slicer and printer settings and filament quality.