Hanslow

Say you had a non-primitive shape defined in some sort of cad file format. Does anyone know any reading material or algorithms for breaking the defined shape down into primitive types, i.e. cubes, prisms, cylinders, spheres, etc. and optimising the primitives used and their size to get a) a best fit and b) best approximation using the smallest number of primitives?

Been trawling the web, but none of my searches have yielded anything close to what I need. Not sure what keywords are best to use in this situation.

I basically need some mathematical topology system in 3D space and looking for a start point.

Cheers

Fuchsrohre

isn't this techniqe known as "tessellation" ?

Hanslow

I thought tessellation was breaking down objects into triangles rather than different object shapes ? I need to do it as solid geometry rather than surface mapping and will have a pool of primitive shapes available that I need to best fit.

I'll have a look to see if tessellation throws anything up, but I have a feeling it's normally for breaking down surfaces into triangles

lightning101

There is a plug in for 3D studio that allows you to do this and even creates a spreadsheet input and output table.


Will have to look a bit more in depth again

Hanslow

Thanks lightning, problem is, it's something we want/need to do with our own 3D modelling software so it's something that we need to write ourselves. We sort of have something already, but I don't think it's very good so was looking for some algorithmic (computational or mathematical) examples to give me some ideas.

If you're any good at reverse engineering code then don't let me stop you hacking it to pieces

Fuchsrohre

Hanslow, try posting on here:
http://www.gamedev.net/community/forums/

Its choc full of graphics programmers

Hanslow

OK I'll have a look see what they have and post something a bit later