Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm a CAD developer and have a surface made up of 3D triangles. I want to split a region of this surface up into a number of patches where each patch has 4 corners. Here's a screen capture of the region of the surface. (triangles not displayed, as they're too dense). last.

The circles/spheres on the boundary lines I am given. They are the corners of the patches on the boundaries. All I need to find is the positions of the corners of the patches inside the region. The black marks I've added on the picture hopefully depict what I'm trying to find. (Although the corners on the boundary lines are equally spaced, that will not necessarily be the case).

EDIT: The corners need to be positioned proportionately. For example, in the picture the top boundary line has a green node/corner adjacent to the blue one which happens to be $\frac{1}{8}$ along the top boundary. The corresponding corner below (i.e. the leftmost black one I've drawn) also needs to be $\frac{1}{8}$ away from the left boundary. It also needs to be $\frac{1}{7}$ of the way "down" from the top boundary line. The actual proportions depend on the positioning of the corners/nodes on the boundary lines.

I've been trying to do accomplish this for many weeks! The "tools" I've been using so far is to create planes, section using the plane, cut out cross section relevant to the region, and walk a proportion along the line. This approach has been plagued with issues. A particular angled plane is not suitable along the entire height of the surface due to surface curvature changes, etc. I would like to approach this entirely differently (i.e. properly!)

Q: What area of mathematics will help me to do this?

share|cite|improve this question
up vote 2 down vote accepted

I think you want mesh parameterization. This is a large area. See these references for instance:

Or do you simply want to convert a triangulation into a quadrangulation?

share|cite|improve this answer
Triangulation into a quadrangulation I believe. All I'm trying to get is these patch corner points. These then get fed into something else (already constructed) which does a lot of mathematical work/interpolation and allows queries at u,v = 7.5,8.25 (for example). I've edited the question a little to go into more detail on the positioning of the corners of the "quads". – PeteUK Apr 14 '12 at 13:32
Google quadrilateral remeshing. – yasmar Apr 14 '12 at 17:36
Thanks for the resources. I'm trying to learn these areas now. Understanding Least Squares Conformal Maps look like a useful tool. Need to get comfortable with some lower-level concepts first. – PeteUK Apr 18 '12 at 9:48

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.