How would I go about constructing the contour of 2d polygon which is formed of only triangles and it can have holes and the external contour can be concave/convex and the holes can also be concave/convex.
From what I'm reading over here it seems that It's exactly the inverse of the triangulation problem. Do you know any articles treating this type of problem?
Are octrees/quadtrees relevant to this?
I guess that you have data in the form of sets of three points, which constitute a "filled" triangle, that these triangles are adjoined along edges, and that all vertices that will be corners of the complete shape are also vertices of all the triangles that touch this point. You would then just have to find all edges that are not doubled, i.e. do not belong to two adjoined triangles.