CGAL users discussion list

[Michel Audette <>]

Hi again, 

I should restate my question. I just noticed that there are only 2 choices between policies under Edge_collapse, the default LindstromTurk_cost and the Edge_length_cost, so it's a question of either implicitly using the former, or explicitly selecting the latter, at least in the official release. If I want one that is different from these, I have to put together a new cost.h file accordingly. 

There is no other cost functions out there that I can use, perhaps in a review directory of some sort? 

I'm looking for something that penalizes the collapse of an edge both of whose vertices have a high curvature and are on the original tissue boundary, so that the resulting simplification is far from the underlying tissue boundary. This, I guess, is what Turk meant in his conclusion by  

If, for example, maximum error is a high priority, then our edge collapse operation could be merged with any of a number of approaches that track maximum error. 

Perhaps this is alleviated somewhat by the mid-point placement policy?

Best wishes,

Michel

On Thu, Jan 6, 2011 at 6:28 PM, Michel Audette <> wrote:

Dear CGAL users,

I have begun playing with edge_collapse() surface mesh simplification,
and I'm trying to reduce a brain surface to its barest essence while
still remaining close to the boundary as possible. This is from a
binary volume where I have obliterated all but one sulcal fold (the
left Sylvian fissure).

I would like to play with various policy options for this surface mesh
simplification, to better preserve the faithfulness of the simplified
surface to that fissure. Are there examples for doing that, e.g. for
penalizing the deletion of an edge shared by two faces at a large
angle to each other, assuming that the faces were faithful to the
tissue boundary to begin with? Is there a way of ensuring also that
the topology is maintained throughout?

Best wishes,

Michel


--
Michel Audette, Ph.D.
R & D Engineer,
Kitware Inc.,
Chapel Hill, N.C.

-- 
Michel Audette, Ph.D. 
R & D Engineer, 
Kitware Inc.,
Chapel Hill, N.C.