>> It's looks like it's based on tubes. You travel a tube and it encounters 
>> other tubes at various angles. Any triangle that is inside any tube is 
>> removed. All edges are smoothed, a little like for a blob.
>
> Yeah, but it looks a little more complex than that. There are large 
> chambers that don't appear to be "tube-like", and there are passages that 
> aren't quite circular, and so on. (Maybe the tube diammeter varies or 
> something?)

My immediate thought was that you take the nVidia "Cascades" demo and invert 
it so you are inside the geometry, not outside it...

Take a look at the "rock generation" part of these slides, they have some 
useful info for building geometry like this, and most of it is directly 
portable to POV iso-surfaces:

http://developer.download.nvidia.com/presentations/2007/gdc/CascadesDemoSecrets.zip

Post a reply to this message