Open CASCADE Technology, The Open Source 3D Modeling Libraries

Open CASCADE Technology (OCCT) is a software development kit (SDK) intended for development of applications dealing with 3D CAD data or requiring industrial 3D capabilities. It includes a set of C++ class libraries providing services for 3D surface and solid modeling, CAD data exchange, and visualization. Originally developed as industrial CAD kernel, OCCT is widely used for development of specialized software dealing with 3D models in design (CAD), manufacturing (CAM), numerical simulation (CAE), measurement equipment (CMM), and quality control (CAQ) domains.

This technology exists from the mid 90s and is available in Open Source since early 2000s under a permissive Open CASCADE Technology Public License. Starting from version 6.7.0 (released end 2013), OCCT is available under GNU LGPL license.

This website is dedicated to contributors of OCCT. If you do not intend to contribute to the development of OCCT but only to use it in your project, please go to the product website:

This website

Since its publication in open source, OCCT has been developed almost exclusively by internal resources of OPEN CASCADE Company. At the same time, OPEN CASCADE recognizes and welcomes the efforts and growing strength of the Open Source Community to improve OCCT. Thus, in 2011, this web site has been created to make OCCT development visible and provide tools for all OCCT contributors to work in the same open environment.

This site provides user authentication, legal documents (see Get Involved), access to OCCT development environment and tools (documentation, issue tracker, Git repository etc., see Resources), and developer's forum.

OPEN CASCADE involvement

Along with maintaining this web site and supporting Open Source contributors, OPEN CASCADE continues active development of OCCT.

OPEN CASCADE also continues to publish a ready-to-use certified version and to support users on