Open CASCADE Community Edition: patches/improvements/experiments contributed by users over the official Open CASCADE library. It was created due to dissatisfaction with OCC's lack of transparency or a public repository. A repository was created at https://github.com/tpaviot/oce
Open CASCADE Technology (OCCT) is an open source software development platform. It includes components for 3D surface and solid modeling, visualization, data exchange and rapid application development. It can be applied in development of numerical simulation software including CAD/CAM/CAE, AEC and GIS, as well as PDM applications.
OCCT traces its history to the mid 1990s.