Re: Voxel Node

T.D. Ritchey ([email protected])
Mon, 12 Jun 95 23:52 BST


Neophytos Iacovou writes:

> I am following this thread with great interest. I have a guestion
> however, if I am using a renderer that does not use Z-Buffer, but
> rather, BSP trees, how do I implement a VOXEL as part of a BSP tree?

Well, my first reaction was to say that it might be easier to implement a
voxel node in BSP, but then I realized that what I thought a BSP tree was
for, and what a z-buffer was for were two different things. I assume then
that you are using the BSP tree by orienting the sub-dividing planes with
the polygons of the scene and then sorting them from front to back (I was
shown BSP trees as space subdivision for ray-tracing optimization). I am
revealing my woefully inadequate understanding of BSP trees and CG in
general right now - be kind.

I believe that the UNIFORM and RECTILINEAR data types would be easy to
implement because the points are all aligned with each axis. You could
pass a plane along (or between) each coordinate.

My first reaction was to say treat each voxel as a cube, and go on from
there traditionally, but I believe that you are going to take a performance
hit by creating a plane for every surface. I think the possible
optimization here comes from the fact that all voxels will be sharing
sides. I am really stabbing in the dark here. Give me a chance to think
on this one and familiarize myself with using BSP trees in that way. The
Brute force method is certainly to just create cubes, or spheres at every
voxel point and then go on rendering from there. That would be an easy
default method to implement, but good luck without an Onyx.

I would appreciate it if you could tell me if I am way off on the BSP tree
stuff, and any ideas you were having.

Cheers,
tim
---------------------------------------------
Timothy Ritchey [email protected]
Jesus College tel: (01)223 576-822
Cambridge fax: (01)223 576-822
CB5 8BL
England