What are LDUs? I see technical people talking about plans and designs in terms of LDUs. I understand it's a measurement unit.
What does it mean and how do LEGO bricks relate to them? Why are they needed?
Common measurements include:
1 brick width/depth = 20 LDU 1 brick height = 24 LDU 1 plate height = 8 LDU 1 stud diameter = 12 LDU 1 stud height = 4 LDU
A 1x1 Brick as 3 Plates in LDUs (via LDraw)
The typical LU (LEGO Unit) measurements are coarser at:
Brick height = 6 Plate height = 2 Stud pitch = 5
Based on the physical dimensions of a LEGO brick, this means that
1LDU == 0.4mm, based on a stud height (1LU) of 1.6mm.