How to Efficiently Triangulate a Concave Shape?

In summary, the conversation discusses the search for a "good" way to triangulate a closed concave shape with the following criteria: minimizing "sliver" triangles and being computationally feasible for a mesh with ~10,000 vertices. The suggestion is to form the convex hull of the polygon and use the Delaunay triangulation method, being careful not to cross existing lines.
  • #1
maze
662
4
I am looking for a "good" way to triangulate a closed concave shape of vertices and edges.

"good" is quite a vague term, but the basic principles I'm interested in are:
1) Minimize "sliver" triangles that are very thin and contain really small angles.
2) Must be reasonable to compute. Ideally it would take less than a day to compute the triangulization for a mesh with ~10,000 vertices on a standard computer (so complete brute force is out).

Here is a diagram (initial shape in black):
http://img394.imageshack.us/img394/3077/concavetriangle.png

If the mesh was convex, a good strategy would be http://en.wikipedia.org/wiki/Delaunay_trianglulation method could work well if I had a fast way of finding the worst possible triangle among a subset of the shape, but I'm having no luck there.
 
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  • #2
Suggestion (it may not be very good): Form the convex hull of the polygon. Use Delaunay, being careful you don't cross any existing lines. Get rid of lines outside original polygon.
 
  • #3
I think the Delaunay triangulization is unique
 

FAQ: How to Efficiently Triangulate a Concave Shape?

What is triangulation of a concave shape?

Triangulation of a concave shape is a process of dividing a concave shape into smaller, simpler shapes called triangles. This is done by connecting points on the perimeter of the concave shape to create a network of triangles that cover the entire shape.

Why is triangulation necessary for concave shapes?

Triangulation is necessary for concave shapes because they cannot be represented by a single shape or polygon. By breaking the shape into triangles, it becomes easier to calculate and analyze various properties of the shape, such as area, perimeter, and angles.

How is triangulation of a concave shape different from a convex shape?

Triangulation of a concave shape is different from a convex shape because convex shapes can be represented by a single polygon, while concave shapes require multiple triangles to create an accurate representation. Additionally, the way the points are connected in triangulation is different for concave and convex shapes.

Are there different methods to triangulate a concave shape?

Yes, there are different methods to triangulate a concave shape. Some common methods include ear-clipping, Delaunay triangulation, and constrained Delaunay triangulation. Each method has its own advantages and is used for different types of concave shapes.

What are the practical applications of triangulating a concave shape?

Triangulating a concave shape has various practical applications in fields such as computer graphics, architecture, and engineering. It is used to create 3D models, analyze terrain, and simulate structures. It is also used in GIS (geographic information systems) to map and analyze geographical data.

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