OpenCASCADE 3D Modeling

OpenCASCADE (Open CASCADE Technology, OCCT) is an open-source software development platform for 3D CAD, CAM, and CAE applications, providing comprehensive 3D modeling and visual data exchange components. Originally developed by Matra Datavision and open-sourced in 1999, now maintained by Open Cascade SAS (part of Capgemini), OCCT is used in FreeCAD, Salome, and hundreds of commercial CAD applications worldwide. Key features include: 3D geometric modeling (comprehensive boundary representation B-Rep modeling kernel with curves, surfaces, solids, and topological operations including Boolean union, intersection, difference, filleting, chamfering, and offsetting), parametric modeling (parametric curves and surfaces including Bezier, B-spline, and NURBS with arbitrary degree and rational weighting), mesh generation (tessellation and triangulation of B-Rep models for visualization and finite element analysis with configurable mesh density), data exchange (STEP AP203 and AP242, IGES, BRep, and STL import and export with support for assembly structure, colors, and names), visualization (3D viewer with OpenGL-based rendering, shaded and wireframe display, real-time rotation, panning, zooming, and selection), 3D constraints and assembly (assembly structure with constraints including coincidence, parallel, perpendicular, tangency, and fix constraints for mechanical assembly modeling), shape healing (automatic geometry repair including surface and curve fixing, shape simplification, and topology repair for imported models), OCCT libraries (TKernel foundation, TKMath math tools, TKG2d and TKG3d geometric primitives, TKGeomBase geometry algorithms, TKTopAlgo topology algorithms, TKPrim primitive creation, TKBO Boolean operations, TKBool boolean operations, TKShHealing shape healing, TKMesh mesh generation, and TKSTEP and TKIGES data exchange), and cross-platform (Windows, Linux, and macOS with C++ API and C# bindings).