The 'kernel' in regards to CAD software is not much different than that of the OS. It is the core around which the application is designed.
ACIS - owned by Dasault, makers of Catia and Solidworks. Neither of these programs use it. It is primarily used by Autodesk and their solid modeling packages, Inventor and Mechanical Desktop. Catia uses a proprietary kernel.
Granite One - owned by PTC, makers of Pro/Engineer. Used since the beginning of Pro/E, but only reently marketed as a kernel. Primarily used to integrate third party applications into your working environment that will allow you to read a Pro/E file without owning a seat of Pro/E.
Parasolid - owned by EDS PLM Solutions, makers of Unigraphics and Solid Edge. Used by Solidworks, MSC, Gibbs, and others. It has a export/import capability that will allow sharing of the solid model between any system that uses the Parasolid kernel. Ben Loosli
CAD/CAM System Analyst
Ingersoll-Rand
717-532-9181
ben_loosli@irco.com