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> Best tool for boolean geometry I’ve personally used. I have good luck with Blender... much more then with Freecad... haven't tried OpenSCAD though...

by YaBomm 5y ago

ur-whale 5y ago
Blender is really nice for certain things, but: 1) Blender is a general purpose 3D tool, and many things that you need for CAD aren't there. Fillets, Chamfers and a robust boolean engine are missing. Also, when you do things in Blender, everything is geared towards how it will look, not towards making sure that things fit each other precisely. For example, getting blender to place an object 3.4mm off the face of a rotated cube along the normal of that face and rotated 33 degrees around that normal is possible, but really not easy. 2) It can be programmed via python, but it isn't the core use case and for programming 3D models using blender, a) the learning curve is very steep b) the resulting code is very verbose because the API wasn't really designed for this use case. c) there is almost no documentation and very little examples of parametric modeling using the blender python API available on the internets. 3) the boolean engine in blender is fast, but it is far less robust than the one in openscad (CGAL-based) and will often simply refuse to produce a model for reasons that are entirely obscure. 4) Even with the newer geometry node engine, Blender is basically centered around a destructive workflow (early steps in the construction of a model can only be changed via undo/redo), and building paramatric models is really not easy unless you get down to the python API.
- b33j0r 5y ago
  Preach! (I shortened my comment to make it more pithy, had a lot of those same thoughts, and appreciate how you fleshed them out!) 5. I write my own blender plugins quite often, and they break with my next `git pull`. Blender moves fast and breaks things ;) I do python professionally and gamedev 3D/VR stuff as a side piece. I spent 5 hours in blender tonight trying to bake an alpha channel. Something I’ve done before. It’s a nightmare to maintain a blender plugin. Because (as you point out) blender is opensource clay, not a surgical scalpel. OpenSCAD is a precision knife.
- floatboth 5y ago
  Someone made a constraint based sketcher for Blender: https://github.com/hlorus/geometry_sketcher https://github.com/hlorus/geometry_sketcher so that is fun.. But of course using a mesh modeling engine for CAD is not the best idea. You generally do want to work in B-rep, if not for precision then for exchange reasons (e.g. export electronic component models as STEP to add to PCB software, import a whole board STEP model from PCB software to build a case for the board)
- YaBomm 5y ago

> Best tool for boolean geometry I’ve personally used. I have good luck with Blender... much more then with Freecad... haven't tried OpenSCAD though...

by YaBomm 5y ago

> Best tool for boolean geometry I’ve personally used. I have good luck with Blender... much more then with Freecad... haven't tried OpenSCAD though...

ur-whale 5y ago

Blender is really nice for certain things, but: 1) Blender is a general purpose 3D tool, and many things that you need for CAD aren't there. Fillets, Chamfers and a robust boolean engine are missing. Also, when you do things in Blender, everything is geared towards how it will look, not towards making sure that things fit each other precisely. For example, getting blender to place an object 3.4mm off the face of a rotated cube along the normal of that face and rotated 33 degrees around that normal is possible, but really not easy. 2) It can be programmed via python, but it isn't the core use case and for programming 3D models using blender, a) the learning curve is very steep b) the resulting code is very verbose because the API wasn't really designed for this use case. c) there is almost no documentation and very little examples of parametric modeling using the blender python API available on the internets. 3) the boolean engine in blender is fast, but it is far less robust than the one in openscad (CGAL-based) and will often simply refuse to produce a model for reasons that are entirely obscure. 4) Even with the newer geometry node engine, Blender is basically centered around a destructive workflow (early steps in the construction of a model can only be changed via undo/redo), and building paramatric models is really not easy unless you get down to the python API.

b33j0r 5y ago
Preach! (I shortened my comment to make it more pithy, had a lot of those same thoughts, and appreciate how you fleshed them out!) 5. I write my own blender plugins quite often, and they break with my next `git pull`. Blender moves fast and breaks things ;) I do python professionally and gamedev 3D/VR stuff as a side piece. I spent 5 hours in blender tonight trying to bake an alpha channel. Something I’ve done before. It’s a nightmare to maintain a blender plugin. Because (as you point out) blender is opensource clay, not a surgical scalpel. OpenSCAD is a precision knife.
floatboth 5y ago
Someone made a constraint based sketcher for Blender: https://github.com/hlorus/geometry_sketcher https://github.com/hlorus/geometry_sketcher so that is fun.. But of course using a mesh modeling engine for CAD is not the best idea. You generally do want to work in B-rep, if not for precision then for exchange reasons (e.g. export electronic component models as STEP to add to PCB software, import a whole board STEP model from PCB software to build a case for the board)
YaBomm 5y ago