# Tidy up mesh topography

I'm working with a mesh generated by an advanced photogrammetry technique http://ir-ltd.net/

The topography is not pretty; here is an example screenshot:

As you can see, the triangle density does not conform to the smoothness of the surface.

I'm guessing this is due to the way the algorithm determines likely candidates for points of interest -- I shave my head myself and the result was uneven; patches of hair probably generate more candidates and hence great a triangle bunch.

Anyway, is there some technique for tidying it up?

Decimation is the only way I can think of. And I will be decimating anyway. So I almost didn't ask the question.

But I am thinking maybe if I first reduce the mesh to a clean evenly distributed mesh, the decimation tool may produce cleaner output.

So, is there any process I can perform to tidy up the mesh topology?

PS This is the 100 K mesh. I also have 500 K and 2 M.

Perhaps you can be helped by the remesh modifier:

http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.62/Remesh_Modifier

It uses the shape of the original mesh but builds it from scratch with even quads. The setting octtree depth controls how detailed the new mesh becomes.

Here I have made a little example. Because I started with a icosphere, there are visible edges of the original mesh. As you can see, there are some more settings to tweak, especially the mode operator can be experimented with.

Start mesh:

With modified:

Modified applied (mode sharp), in edit mode to show even topology:

Modifier applied (mode smooth):

For such uneven vertex distribution sculpting with dynamic topology and simplify toolcould work well. There was a great explanation of this problem around here no more than a day or two ago: