I recently needed a tool like this ... and sadly concluded that there's no clear winner in the free software world. Sketch-up's non-Linux presence is a pain, b

I recently needed a tool like this ... and sadly concluded that there's no clear winner in the free software world. Sketch-up's non-Linux presence is a pain, but can be worked around - the web version's useless for me, but again you can download the last .exe version they released still, from the official page (albeit they've hidden it). FreeCAD and LibreCAD are worth diving into just because they're going to be around for a while, and at least one of them seems to be well supported. Blender's another option, and though it doesn't align feature-wise quite as well, and has a steeper learning curve - learning it is going to be useful forever, and for a wider range of use cases.