APS-Spline library developed from 1978-1988 a software toolkit programmed in FORTRAN for the definition and interrogation of B-spline represented curves. Among the unique features were the approximation through knot removal and the recursive intersection algorithms for curves and surfaces. The development was heavily influenced by industry, first the Aircraft division of Saab in the Nordic Research project Geometric Product Models (GPM), in then German and Norwegian companies part of the German Norwegian Research Project Advanced Production Systems (APS) (1981-1987). Introdcution of APS B-Spline library.

                      In 1989 the development of a SISL – SI Spline Library (alter renamed to SINTEF Spline Library) started due to a development contract with the Workstation Division of Hewlett Packard to be used in the HP CAD-system Solid Designer. After the development was completed a close cooperation started first with HP, then with CoCreate and now with PTC as the ownership of the CAD-system has changed over the years. SISL is implemented in C, and is available under the GNU-GPL License as well as commercial licenses. For more info go to the SISL web-pages.

                      From the mid 1990s a development of a C++ spline library GoTools started as our project work gradually replaced C by C++. GoTools has dominantly been used as a container for program codes coming out of software projects. In 2009 GoTools have been through a major brush-up to better support isogeometric analysis. Volumetric NURBS representation has been introduced as well functionality reflecting the requirements from analysis to geometry representation. For more info go to the GoTools web-pages