OpenCascade is pretty much the only open source CAD kernel. There is brlcad, but that can only do CSG.
We tried parasolid, then we got forced into using ACIS. We didn't really end up with much of a complete product in the end as this was government funded research.
We tried parasolid, then we got forced into using ACIS. We didn't really end up with much of a complete product in the end as this was government funded research.