[Macuyiko]

This reminded me of coming across LeoCAD (https://www.leocad.org/ - first release in 1997!) as a kid and playing around with it for endless nights, wondering how close it was to whatever tool Lego was using in-house.

Looking at screenshots of older versions gave a burst of nostalgia.

[Freak_NL]

LeoCAD is really nice and smooth to work with, and on Linux a much better experience than Lego's own Bricklink Studio. Unfortunately, for instructions you can't really get away from Studio, and while importing the model made in LeoCAD works for 99% of the bricks, you tend to end up with one or two types of brick misaligned, flipped, rotated, or missing.