Cutting / sectionning a closed mesh

Blitz3D Forums/Blitz3D Programming/Cutting / sectionning a closed mesh

_33(Posted 2007) [#1]
I've got a quicky for the experts: Anyone know of a simple technique to cut a closed mesh in two parts? The two parts must also be closed, but the cut portion of the new mesh will return a surface handle to be textured.

Any hint on doing this will be well appreciated. Cheers.


b32(Posted 2007) [#2]
In the code archive, there is a program that can use CSG. Maybe you could see if it does what you need ?
http://www.blitzbasic.com/codearcs/codearcs.php?code=560


_33(Posted 2007) [#3]
Holy cow!!! It does that and much much more of things that I wish I could of done previously. That's one great piece of code.

So I guess it partly answers my need as I may use this to make parts of a mesh and figure it out accordinly. There might be some routines that will do clipping just as I wish in this, like a clipping plane + closing the mesh at the same time.

Thanks! Cheers.


_33(Posted 2007) [#4]


That CSG system is nice, but definately not fast enough for realtime, nor is it polygon perfect. Also, the resulting mesh might have triangles that leave opening, which would break most shadowing systems. Right now I'll put this on the side, but it's quite a nice piece of code that I hardly understand!

Yet, there was this clipping plane demo from big10p that I got really impressed in the speed it was able to clip. The only thing missing on it is to close the mesh. I'll have to figure that one out.


Stevie G(Posted 2007) [#5]
Look for Fredborgs Tessalate function in the archives.

If you use Big10ps plane clipping code and feed the intersecting points into Freds function ( in a clockwise order I think ) then you should be able to create the poly's to close the shape.

Stevie


_33(Posted 2007) [#6]
I'll put news on my advancements on this if any this comming week. If I have it working, I'll post what I did.

Cheers.