Triangulated Irregular Networks from qhull

I 开发者_JAVA百科wanted to create TINs from 3D points (about 7 million in every file) using qhull.

can anyone suggest a place where i could probably see how to do this? thanks!

I've never used QHull since it is hard to integrate as a library into an existing project. Try out Triangle; it is specialized for 2D and is very easy to use (it comes with an example of how to call it from other C code).

I could recommend you a software package called Streaming Computation of Delaunay Triangulations. On a normal computer it can compute

Delaunay triangulations for large, well-distributed data sets in 2D and 3D which can be greatly accelerated by exploiting the natural spatial coherence in a stream of points.

In terms of performance:

We compute a billion-triangle terrain representation for the Neuse River system from 11.2 GB of LIDAR data in 48 minutes using only 70 MB of memory on a laptop.

Here is teaser image on how it works:

You can check out this video explaining their method/software.

Wiki says,

A TIN comprises a triangular network of vertices, known as mass points, with associated coordinates in three dimensions connected by edges to form a triangular tessellation. Three-dimensional visualizations are readily created by rendering of the triangular facets. In regions where there is little variation in surface height, the points may be widely spaced whereas in areas of more intense variation in height the point density is increased.

A TIN is typically based on a Delaunay triangulation but its utility will be limited by the selection of input data points: well-chosen points will be located so as to capture significant changes in surface form, such as topographical summits, breaks of slope, ridges, valley floors, pits and cols.

MATLAB can generate 3-D Delaunay tesselation and n-D Delaunay tesselation using Qhull.

3-dimensional Delaunay tessellation - tetramesh is used to plot the tetrahedrons that form the corresponding simplex