Parasolid

Parasolid is a geometric modeling kernel developed by Siemens PLM Software. It provides the core technology for representing, creating, and manipulating 3D solid and surface models in CAD, CAM, and CAE systems. The kernel supports boundary representation-based modeling with NURBS surfaces and a broad set of solid and surface operations.

Key capabilities include robust Boolean operations, fillets and blends, chamfers, shells, sweeps, lofts, revolutions, and variable-radius features. It emphasizes numerical robustness, precision, and consistent topology across operations, enabling reliable design intent preservation as models evolve.

The Parasolid API is typically exposed to host applications via C++ interfaces, supporting both history-based parametric workflows and direct editing. It also handles data exchange and interoperability with standard CAD formats to facilitate collaboration across software packages.

Parasolid is licensed to a wide range of CAD and related software. It underpins several widely used tools, including SolidWorks, Solid Edge, Siemens NX, and Onshape, making it one of the best-known geometric kernels in the industry. It competes with other kernels such as ACIS and CGM.

Since its introduction in the 1990s, Parasolid has been continuously developed by Siemens, expanding its modeling features and performance for large assemblies and complex surfaces.