GTS stands for the GNU Triangulated Surface Library. It is an Open Source Free Software Library intended to provide a set of useful functions to deal with 3D surfaces meshed with interconnected triangles. The source code is distributed under the terms of the GNU Lesser General Public License (LGPL).

The code is written entirely in C with an object-oriented approach based mostly on the design of GTK+. Careful attention is paid to performance related issues as the initial goal of gts is to provide a simple and efficient library to scientists dealing with 3D computational surface meshes.

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 (adapted from the fine work of Jonathan R. Shewchuk).
• 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.
• Simple try/catch/throw exception-handling interface using cexcept.