Home Page: http://opensource.studionestbarcelona.com/studio_NEST/melena.html
Project Page: http://github.com/studioNEST/Melena
Language: C++
Platform: Windows, Linux
License: LGPL v3
Sponsor: StudioNest

Momentum allows you to do very precise rigid body dynamics with high performance including full control over the simulation using the ICE framework.

Home Page: http://opensource.studionestbarcelona.com/studio_NEST/momentum.html
Project Page: http://github.com/studioNEST/Momentum
Language: C++
Platform: Windows, Linux
License: LGPL v3
Sponsor: StudioNest

Home Page: http://opensource.studionestbarcelona.com/studio_NEST/kratos.html
Project Page: http://github.com/studioNEST/Kratos
Language: C++
Platform: Windows, Linux
License: LGPL v3
Sponsor: StudioNest

With StudioNEST Brigks you can build very efficient rigs that don’t require to setup overly complex object hierarchies. Since the source code of the kinematics solvers is provided, implementations of matching kinematic solvers can be achieved for other packages as well as standalone applications.

Home Page: http://opensource.studionestbarcelona.com/studio_NEST/briqks.html
Project Page: http://github.com/studioNEST/Brigks
Language: C++
Platform: Windows, Linux
License: LGPL V3
Sponsor: StudioNest

Home Page: http://pyode.sourceforge.net/
Project Page: http://sourceforge.net/projects/pyode/
Language: C++
Platform: Windows, Linux, OSX
License: GNU Lesser General Public License or BSD-style license.

In the nearest neighbor problem a set of data points in d-dimensional space is given. These points are preprocessed into a data structure, so that given any query point q, the nearest or generally k nearest points of P to q can be reported efficiently. The distance between two points can be defined in many ways. ANN assumes that distances are measured using any class of distance functions called Minkowski metrics. These include the well known Euclidean distance, Manhattan distance, and max distance.

Based on our own experience, ANN performs quite efficiently for point sets ranging in size from thousands to hundreds of thousands, and in dimensions as high as 20.
(For applications in significantly higher dimensions, the results are rather spotty, but you might try it anyway.)

The library implements a number of different data structures, based on kd-trees and box-decomposition trees, and employs a couple of different search strategies.

The library also comes with test programs for measuring the quality of performance of ANN on any particular data sets, as well as programs for visualizing the structure of the geometric data structures.

Project Page: http://www.cs.umd.edu/~mount/ANN/
Language: C++
Platform: Linux, Windows, OS X
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.

Home Page: http://gts.sourceforge.net/
Project Page: http://sourceforge.net/projects/gts/
Language: C
Platform: Linux, Windows, OS X
License: LGPL

• Used by many game companies in AAA titles on Playstation 3, XBox 360, Nintendo Wii, PC and iPhone
• Modular extendible C++ design with hot-swap of most components
• Optimized back-ends for pthreads/Win32 Threads multi-threading and PS3 Cell SPU
• Preparation for OpenCL data parallel optimizations for upcoming Bullet 3.x
• Discrete and continuous collision detection (CCD)
• Swept collision queries
• Ray casting with custom collision filtering
• Generic convex support (using GJK), capsule, cylinder, cone, sphere, box and non-convex triangle meshes.

• Rigid body dynamics including constraint solvers, generic constraints, ragdolls, hinge, ball-socket
• Support for constraint limits and motors
• Soft body support including cloth, rope and deformable
• Bullet is integrated into Cinema 4D, Lightwave and Blender, and a Houdini and Maya Plugin is available
• Supports import and export into COLLADA 1.4 Physics format
• Support for dynamic deformation of non-convex triangle meshes, by refitting the acceleration structures

Home Page: http://bulletphysics.org/
Project Page: http://code.google.com/p/bullet/
Language: C++
Platform: Linux, Windows, OS X
License: ZLib License, free for commercial use.

Home Page: http://www.ode.org/
Project Page: http://www.ode.org/
Language: C/C++ (the public APIs are all C)
Platform: Linux, Mac OS X, Windows
License: New BSD or LGPL (your choice)