K, i tried all this. It works as shown in tut. Thats nice.
What is very very nice is how fast it is. The last few days I was practicing retopo manually in maya, this is no fun at all, and very labor intensive. The retopo workflow in the tut took only a few moments! I have an older 2009 desktop (although a bit newer GPU, which is important for this), so I was concerned things would just be slower in general. But no hangups at all really.
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In this image the green one is the original tris scan. the middle is the new quad model of that scan, and the 3rd is obviously the new base. It was nice to see that the levels between the high and low are also created and can be saved individually.
One thing to look out for, is that the quad model is higher polly count than the original tris. I guess it takes more quads to displace a mesh than tris, even though it takes an extra edge to make a square from tris than with quad.
Apparently while a quad is only 4 edges, and a square tris is five edges, on a large complex model (or terrain) you get much lower polly counts with tris, because every tris square can deform down the middle, but quad can't and will give you non planar faces... just interesting to finally see exactly how that works at a manageable level.
Probably nothing new to most of you in that statement either, but it is worth being written down someplace.
Now I have to learn (finally) to bake the high to low (not just understand the principal

). And from the resulting mesh, I will be able to create a new model that is not derivative form the original.
MASIVE time saver for modeling in this stuff. Which you all also may have already known, since we have had plenty of photo scan threads. But on the other hand I have not seen hardly any renders with models based on scans in them, that I now about. I just figure it is all the intermediate steps that stops people from doing it?
If I can get through an entire workflow for this, I will defiantly be doing it often. Its just so much faster

And with all the free models to build from at 123D models downloads pages, its too easy not to do it.
Hope this helps someone.