[vtkusers] Volume rendering with texture mapping

[Dimitris Agrafiotis]

Dear all

There are some things I would like to make clear about texture mapping 
and volume rendering.

1) First of all can I have texture sizes that are not a power of 2? 
2) I have a volume of size 216x216x183. What target size texture should
   I use? 
3) If I use a 256x256 texture size what happens with the extra   
   points? Are they interpolated , do I have to pad my volume with 
    zeroes, or does this happen anyway?
4) If I intermix the above result with a surface generated from the 
   original 216x216x183 volume will there be any problems? 
5) And finally, when I render the volume with textures, I would like a 
   specific part of the volume (a subvolume - let's say a cube) to be 
   rendered differently (let's say with ray casting or with more 
   samples.) Can I do that, and if yes, what would be the simplest way 
   to do it? 

Sorry for asking so many things. 
Thanks in advance 

Dimitris