CGAL users discussion list

[Manu Kaul <>]

Hi all,

I used the "Triangle" library from http://www.cs.cmu.edu/~quake/triangle.html by Jonathan Shewchuck to generate a Delaunay triangulation 

of my raw x,y,z points. I am trying to create an indexing structure and some distance bounds that make the shortest path calculation on a 

terrain faster + some other queries like range queries, and k-nearest neighbour queries as well. 

I noticed that in order to do some of these things I might need CGAL, but I understand that the learning curve can be quite steep. 

The things I need to do are :

1. Generate TINs at multiple levels of details by introducing Steiner points. 

2. Being able to access the triangles and its adjacent triangles in raw form (like 0 1 2 vertices of triangle in counter-clockwise format)

so that I can feed it to a "Chen and Han" shortest path implementation by O'Rourke (http://cs.smith.edu/~orourke/ShortestPaths/) 

3. Have the ability to compute the slope of each triangle and also all its interior angles.

4. Need to be able to *project* onto the terrain the 3D euclidean line between any two points of the terrain.

5. Generate a Voronoi diagram from the Delaunay (Triangle generates this too)

Someone who used CGAL mentioned that traversing over faces of a triangulation in CGAL can be quite cumbersome and that I should

instead convert it to a polyhedron and use the iterator there. So I just want to understand if CGAL will be able to help me with all the 

things I need to do and if I might get stuck halfway? Hopefully CGAL will not be overkill for what I am trying to do? I found another C++

library that used the DECL (http://www.holmes3d.net/graphics/dcel/), would this be easier to use than CGAL for what I am trying to achieve?

I ask since I am not going to do very complicated computational geometry related work on the surface, if CGAL would be too much to work with?

Thanks,

Manu

--

The greater danger for most of us lies not in setting our aim too high and falling short; but in setting our aim too low, and achieving our mark.
- Michelangelo