Hacker News Reader

Comment by samwillis | Hacker News Reader

The fundamental problem is that there isn’t a good enough open source parametric kernel. FreeCAD uses OpenCascade which is the best available, but quite dated, FreeCAD is pushing it to its limits.

View on HN

Is there a good description of what such a parametric kernel does? Or are there any alternatives to OpenCascade?

Edit, found this article with a little explanation: http://mikeestee.com/2012/03/open-source-parametric-cad/

The two big CAD kernels are Parasolid, owned by Siemens, and Acis, owned by Dassault. Both of them are proprietary, quite pricey, and light years ahead of OpenCascade in capability and stability. The current state of open-source CAD is very sad.

Thank you! Based on this, I found the wikipedia article: https://en.wikipedia.org/wiki/Geometric_modeling_kernel

I wonder if there is currently a concentrated open-source effort in this direction, like a greenfield project for today's needs (including capabilities toward design optimization, subtractive and additive manufacturing, while addressing any shortcomings in OpenCascade).

Step files work well for interchange but have no parametric features as far as I can tell. They are also proprietary. For whatever reason, I haven’t seen any serious effort to make an open source cad kernel. Maybe one reason is unlike 3D modeling for artistic domains, very few users are capable of working on software and there’s probably much lower pressure to use software to automate design.

I don’t really see a need to focus on subtractive and additive manufacturing in the kernel, although some hints in the UI for a particular program would be useful. Analysis and optimization predates 3D cad, in a way so it would be interesting to see what could be done from scratch.

And interestingly, Dassault’s Solidworks uses parasolid and not Acis.

Reply on news.ycombinator.com