GTS stands for the GNU Triangulated Surface Library. It provides a set of useful functions to deal with 3D surfaces meshed with interconnected triangles. A brief summary of its main features: * Simple object-oriented structure giving easy access to topological properties. * 2D dynamic Delaunay and constrained Delaunay triangulations. * Robust geometric predicates (orientation, in circle) using fast adaptive floating point arithmetic. * Robust set operations on surfaces (union, intersection, difference). * Surface refinement and coarsening (multiresolution models). * Dynamic view-independent continuous level-of-detail. * Preliminary support for view-dependent level-of-detail. * Bounding-boxes trees and Kd-trees for efficient point location and collision/intersection detection. * Graph operations: traversal, graph partitioning. * Metric operations (area, volume, curvature ...). * Triangle strips generation for fast rendering.