[brlcad]

The topic has come up and been a point of discussion, especially developing something akin to the ACIS or Parasolid kernels, but open source. In many areas, BRL-CAD's capabilities far exceed what OpenCascade provides, particularly w.r.t. CAE features, and in others it is noticeably lacking (e.g. export to polygonal). Couple years of effort have been invested in developing a new C++ API for exactly this purpose (codename "MOOSE").

Current dev focus is on conversion, rendering, and GUI modernization.

[ofrzeta]

I wonder why do you care about rendering? There are many good open source renderers out there, now. For instance can't you just export the geometry and render with Yafaray?