The method here is faster than most other free source codes available on the internet. It is about 4x faster than Meshlab, which is already fast. Using multi-core programming, it could even be faster.
It has the following features:
[li]Threshold based, therefore faster than sorting based methods
[/li][li]Since the Quadric Matrices are symmetric, only 10 elements are stored & computed per Matrix
[/li][li]Non-closed meshes are supported by extra treating mesh borders
[/li][li]Simplifies 2.000.000 triangles to 20.000 triangles in 3 seconds on a Core i7
The code is short and easy to use in case you need to adopt it to your project. You can fetch the C++ Project with source here: (about 300 lines for the main part, contained in Simplify.h )
Here a comparison: Program output (left) and Meshlab (right).