There are three common commercial modelling kernels that are licensed to various CAD manufacturers and are therefore used in different CAD programs:
- Parasolid, developed by Siemens PLM Software (formerly UGS) and used by NX, Solid Edge and SolidWorks, among others. File name extension *.xt or *.xb
- ACIS, produced by Spatial Corp, part of the Dassault Group. File name extension *.sat
- C3D, produced by C3D Labs, belongs to the ASCON Group. File name extension *.c3d
At merle.tech, we use Parasolid (SolidWorks or Schapr3D)