@pro@OpenSCAD Ah, that would have been even simpler in the design tree, just putting the three notches into a single sketch to pocket, and dropping the multi-transform, which was there just as an example for modeling with less drawing in a sketch.
I'm curious about a few things...
Are you assuming mm as the base unit when writing a STEP (current typical practice in OpenSCAD AFAIK) or are you including some way of explicitly defining the base unit?
Are you preserving color and representing it in the STEP?
When (on livejournal) you say "possibly square or round" do you mean you are representing a rectangular face as a single square instead of as two triangles as it would be in an STL, and stitching curves back together at some epsilon (like the "arc welder" plugin for 3d printing slicers)?