View Full Version : nodes + buffers + passes?

09-11-2007, 11:09 PM
I'm wondering if Lightwave could be forced to evaluate a surface multiple times/ways and save each as a separate file.

For instance, what If I wanted Lightwave to process an occlusion node/pass, but not apply it to the image rather just save it out to a file.

I guess this would be like using nodes to create passes?

It would be great to be able to define a custom "output" for the nodes, such as a custom matte. If I called it "matte1" It would be added as an end input for the node editor, then you could, per surface, plug any value or shading you wanted into "matte1" to create your pass on a per-surface basis. This would let you create arbitrary mattes for compositing purposes.

Perhaps in a pixel filter you could then specify to output "matte1" to a file. It wouldn't show up in the rendered RGB or any other current LW buffer. If you didn't specify an output file, the data could be tossed or not processed at all.

You could call another one "occlusion" and plug your occlusion node into the output, but perhaps occlusion would only need to be evaluated for three items/surfaces in your scene, so you only would connect it in those three surfaces... perhaps connecting a white value for other surfaces so that they don't interfere.

With this sort of system you would have limitless user-definable passes instead of the ones that Lightwave currently processes. Sometimes this would add to the render time, but probably less than it would to create separate scenes, objects, and renders for each pass with the current system. Plus, Lightwave would only have to process the geometry once, after that it's just raytracing and shading.

Does this make sense? Is this crazy?

Right now Denis has a node that saves APS information at render time, so it seems feasible the same could be done for custom surface information.

The possibilities are tantilizing... it would seem.

09-11-2007, 11:57 PM
I think Denis has some other nodes that can pull out buffer information.

09-12-2007, 12:22 AM
I'll go see if I can find them.

But as far as I know, there isn't a way to define special buffers, is there?

09-12-2007, 12:39 AM
Wow. Looks like Denis' plugins do do just what I am talking about (with a 3 buffer limit). Looks like they write to LW buffers instead of external files, but I guess that's okay if you don't need the LW buffers.

Very cool. He is always five steps ahead of whatever I can get my mind around.

09-12-2007, 12:56 AM
well, strike that last one. they write to external files also...

I'm trying to figure out the nuances of this. It's a bit tricky.

09-12-2007, 01:27 AM
hmm. It causes some serious serious slowdowns under certain circumstances (photoreal motion blur).