**comp.graphics.algorithms**

## Subject: **Re: Mesh Correction Algorithm - Academic Question**

Check out Greg's papers:

http://www-static.cc.gatech.edu/~turk/pubs.html

In particular:

http://www-static.cc.gatech.edu/~turk/my_papers/retile.pdf

- Saty

Adam Hartshorne wrote:

> Hi all,

>

> I wondered if anybody had any suggestions, links to academic papers etc

> about the following problem that I face as part of my research.

>

> I am running an algorithm (which I can't really talk too much about)

> which achieves the following. Given a set of lets say point cloud data

> (points which are known to lie on a surface), my algorithm takes a

> random triangular mesh and fits it to this data, such that on conclusion

> of the algorithm the mesh represents the surface from which the range

> data was taken. Now my algorithm achieves what I will describe as a good

> representation of the surface.

>

> However, two problems seem to arise,

>

> 1) In small areas, some faces of the mesh are such that the following

> sort of thing has occurred. The vertices of these faces appear to

> reasonable (i.e. sensibly position for the surface), however the faces

> have what can best be described as collapsed ontop of each

> other(Difficult to describe in text). So two faces lie across each

> other. Now I could simply take the final vertex positions of all faces

> and show how retriangulate the surface, but the vast majority of faces

> are fine.

>

> 2) The concentration of vertices can be highly bunched in certain

> localised areas, i.e. non even concentration across the face. I am not

> looking for an even distribution, but in some areas that are fairly

> planar they are really way too many vertices (and hence faces) which I

> think is redundant information. Obviously areas of great variation in

> surface need to be adequately represented.

>

> Could anybody suggest a solution, for 1) some sort of retriangulate

> certain problematic areas and 2) some sort of smoothing, to attempt give

> a better overall surface likeness.

>

> Visually the problem been at the moment, when I texture my final mesh it

> can sometimes appear a little bumpy.

>

> For 2) I have tried the Jacobi Laplace Smoother available through

> OpenMesh (I know nothing really about mesh smoothing), but found that

> this technique redistributed my vertices but also moved them such they

> no longer represented the surface particularly well.

>

> Now I understand this is hard to imagine in text alone and anybody

> wanting to help I could send a mesh or picture if that made things clearer.

>

> Any help would be much appreciated. I doubt anybody has the magic bullet

> to this problem but a discussion / starting suggestions is what I really

> need at this moment.

>

> Adam

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