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OpenGLRox
08-02-2001, 08:37 AM
Does anyone know of a dowloadable program that will load a model (3ds, obj, etc), and allow the user to decrease or increase it's polygon count.

I imagine it wouldn't be too difficult to write an application to do it, but time is money, and if someone already has one out there, no sense in re inventing the wheel.

Thaks for any help.

gtada
08-02-2001, 10:38 AM
Well... I know of some commercial apps that do. Many 3d packages have decimators built-in (like Maya and Max). Also if I remember correctly, I think Polytrans has a good one. Do you have a lot of models to decimate?

OpenGLRox
08-02-2001, 10:53 AM
Not a lot of models. I have an angelfish which has like 4k faces in it, and considering it will be in the water under your feet, that is WAY overkill for definition.

As I was looking at the model in wire frame mode, I could almost see how you could write code to merge vertices together to decrease the face count.

I thinking there must be something out there that will do it. Some little utility. *Shrug*

ffish
08-02-2001, 06:33 PM
I was looking at decimation a while ago. I remember I found an OpenGL demo app that reduced and then recreated polys. Don't remember if it had source as well. I was specifically looking at Hugues Hoppe's research. google will probably turn up his website or SIGGRAPH has some of his old papers online somewhere. There are two methods for decimation - vertex collapsing or edge collapsing. HH's work is based on the latter and is good because the alg's allow full recreation of the original model for scaling your app.

I'll have a look when I get home and see if I can find some links or the demo for you.

Hope that helps.

ffish
08-02-2001, 09:24 PM
Here's a link to the demo decimation implementation that I was talking about (I think this is the one I remember):
http://www.cs.cmu.edu/~garland/quadrics/

Down near the bottom is the link to the software to download plus there are papers from the authors' presentation pdf's.

Hope that helps.