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Basiror · DeleD PRO user Joined: 12 Dec 2007 Posts: 59

In the help file you got an example of a concave polyline,

now I tried several polylines looking like a "U" that are triangulated to a convex shape

I guess you falsely use a delaunay triangulation if convexionate is not selected

the yellow marked area should not be part of the triangulation

delaunay triangulations are always convex, for concave polygons you need an algorithm like "sweep line"

Mr.Fletcher · Posted: Sat Dec 15, 2007 5:10 pm Post subject:

It's just a matter of rendering then. If you've got a concave polyline consisting of one polygon, DeleD might still render it convec, although the data itself if correctly concave. If you're annoyed by that, you've got to triangulate the polygon manually.
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Basiror · DeleD PRO user Joined: 12 Dec 2007 Posts: 59

how to do that?
create several polylines, merge them and weld the vertices? at the shared edges?

Jeroen · Posted: Sat Dec 15, 2007 5:45 pm Post subject:

You can use the Triangulate function for that. Or the Optimize function, which will break up the concave polygon in convex pieces. Using Optimize usually gives better results than triangulation.

Edit: moved to DeleD forum because it is a question, not a bug.

Basiror · DeleD PRO user Joined: 12 Dec 2007 Posts: 59

I just created several convex polylines and merged them, implementing a sweep line algorithm to triangulate them for rendering is really no fun Smile

corner cutting would be a option is conjunction with plücker coordinates to determine line contour intersections inside the cut triangle

Jeroen · Posted: Sat Dec 15, 2007 6:05 pm Post subject:

Basiror · DeleD PRO user Joined: 12 Dec 2007 Posts: 59

the convexionate was not an option in my case since I wanted to do some extruding and vertex adjustments, merging several quads did the job though