A renderer that combines techniques?

[Kira Vakaan]

Hi all,

So I was thinking... multi-threaded programming is a forever old concept. Rendering is something that lends itself nicely to a threaded model. You have multiple threads all operating on shared scene data and all outputting samples to a shared buffer. Has anyone tried making each thread do a different thing? Why couldn't one thread be doing bidirectional path tracing while another does SPPM? It seems like a brilliant idea: render threads could all contribute to faster convergence by using rendering techniques that support the weaknesses of the techniques used by their neighboring threads. I'm positive someone has had this idea before me. Has anyone done it? Anyone have an interesting link? Please do share, that would be awesome to see.

[paco]

You could give it a go yourself - just launch multiple instances of lux with different parameters using 1 thread each

[Kira Vakaan]

You could give it a go yourself - just launch multiple instances of lux with different parameters using 1 thread each

Hah, that's a thought. Getting it all merged together later would be a problem though. I suppose one could just impose the images upon each other in GIMP or something, but that's not quite the same.

I'm really surprised, actually. I've been researching some of the big name renderers, and none of them boast such behavior. Could it be that this hasn't been done? Is this actually an original idea? Let me know if anyone has even heard of something like this talked about.

[moure]

You could try what paco suggested and merge the resulting .flms with luxrender, not the images with gimp
the merge flm requirement iirc is only the size of the image and the light groups. If the scene is the same you can ,merge flms made with different render settings, like you suggest

[jeanphi]

Hi,

The main issue is that different rendering techniques have differing data structure requirements and the memory requirements of running several in parallel could be too high to be practical.

Jeanphi

[Kira Vakaan]

the merge flm requirement iirc is only the size of the image and the light groups.

Oh, I was under the impression that the integrators must also be the same and that's why I suggested GIMP. If this isn't a requirement though, then yes, that would be much better.

The main issue is that different rendering techniques have differing data structure requirements and the memory requirements of running several in parallel could be too high to be practical.

I see. As someone who hasn't spent too much time in LuxRender's code, what structures are required that would incur a large memory usage when existing together? Obviously photon maps for Exphotonmap and SPPM, and a tree of hit points for SPPM.. hmm, what else is there?

I find this kind of thing fascinating. I'd really like to give it a go myself.

[jeanphi]

Hi,

The hit points can represent a huge amount of memory, the other data is the film buffer itself which can become huge and can not always be shared between rendering techniques.

Jeanphi

[Pilchard123]

Does anyone have a scene (Well, I suppose two scenes really, to use different render techniques) that could benefit from different techniques? I have two machines and I'd quite like to see how this would turn out.