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Comment by wlesieutre | Hacker News Reader

I just found that linked in r/3dprinting last night on a discussion about the Autodesk's new Fusion 360 bullshit, it's on my list to try out!

If SolveSpace doesn't pan out for me I'll try OpenSCAD next, but I gather there are some issues with that modeling approach where fillets/chamfers are much more challenging to create than they are in a graphical modeller.

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With OpenSCAD, you don't have fillets as part of the language, but you can do chamfers or machinable parts easily using the minkowski sum operation, which basically places an object of your choice on every point along the surface of another object. I've used this to do insets and outsets, radiused corners, and all sorts of other funky stuff.

However, if you want that sort of operations you would probably be better off with cadquery, which is basically the engine behind FreeCAD, with a really powerful Python interface. It has native support for face operations like fillets.

No idea if I'm doing something wrong, but minkowski operations seem to cause OpenSCAD's preview and rendering to become extremely slow real quick, on the order of minutes for models with several such parts.

minkowski and hull operate on every vertex in your object mesh - this means they need to a) convert the solid into a mesh and b) do math for every combination of vertices in said mesh. That's O(n^2) operations for objects of complexity n. This means that they are much slower than csg operations (that operate on the underlying geometry rather than the mesh). They are definitely the slowest (but most powerful) operators in OpenSCAD. If you're doing something like minkowski-adding a sphere to a complex shape, use $fn=(some low number) on the sphere to reduce face count and speed things up initially while you're hacking around, then increase it again before final render.

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