So ... Bearer of bad news here: I've tried this on a model I had lying around, and ... :-\ box.scad is an old, somewhat complicated electronics enclosure wher

So ... Bearer of bad news here: I've tried this on a model I had lying around, and ... :-\ box.scad is an old, somewhat complicated electronics enclosure where I experimented with building a non-trivial, fully filleted model with scad. The model has quite a lot of "natural" booleans (eg holes and such), but also, the fillets are implemented either: - with a ton of procedurally generated minkowski sums (offsets) combined with booleans. - with hulls of far-apart spheres TL;DR: as far as I can tell, fast-csg does not render the model properly :-( speedup with fast-csg is decent (~5x) only at very low $fn speedup is entirely underwhelming when $fn gets high minkowski offsets likely gobble up the bulk of the render time This also made it very clear that render times aren't linear at all when $fn grows, and this is both true for traditional openscad and fast-csg. Your mileage may get much better if you steer clear of hulls and minkowski sums, and to be fair, I'd need to run a benchmark with no minkski in it. Benchmark: old : time openscad -o z.stl box.scad new : time openscad-nightly --enable fast-csg -o z.stl box.scad $fn = 5 old = 6.8 sec new --enable fast-csg = 1.2 sec x 5.6 $fn = 10 old = 15 sec new --enable fast-csg = 3 sec x 5 $fn = 20 old = 67 sec new --enable fast-csg = 25 sec x 2.68 $fn = 40 old = 427 sec new --enable fast-csg = 369 sec x 1.15