SINGULAR
Science, Math, Geometry, Software - Singular. Computer algebra system for polynomial computations.
https://www.singular.uni-kl.de/
CGAL - Computational Geometry Algorithms Library
Science, Math, Geometry, Computational Geometry - CGAL - Computational Geometry Algorithms Library. A collaborative effort to develop a robust, easy to use, and efficient C++ software library of geometric data structures and algorithms.
https://www.cgal.org/
The Geometry Center Welcome Page
Science, Math, Geometry - Geometry Center. Web site for the (now closed) Center for the Computation and Visualization of Geometric Structures at the University of Minnesota.
http://www.geom.uiuc.edu/