Samstag, 14. November 2009

SVO-Voxel-Raycasting

Here some demos of my new sparse-voxel-octree (SVO) rayster.

Technical details:

-Storage: ca. 100 bit/voxel
-Stack-based
-Uses a variant of persistent threads


Demo download: SVO-Demo-Cuda.2.3.7z

Kommentare:

  1. hi there, i tried it out.. but it doesnt seem to start after the console is done doing its thing?

    im on xp with an nvidia 8600 mobile intel core 2 duo 2.4 ghz

    nvidia drivers should be cuda compatible as i run a few other things that require it.

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  2. Hi, do you have cuda 2.3 installed ? I'm not sure which demo you tried - I uploaded a new one yesterday with separate demos for 8000+ cards and G200+ cards. The difference is that the G200+ cards have more registers, so those executables wont run on 8xxxx cards.

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  3. Just a general question: would a SVO pathtracer be more efficient than a triangle pathtracer, because of the inherent multiresolution advantage of SVO?

    Sam

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  4. Thats a good question. The answer depends mostly on what kind of scene you are focussing on. For a common character like model with up to 5M polygons, you will have 60fps even with common rasterization. If you have much more polygons and a static scene, raycasting gets more interesing. The advantage of using voxels is, that the raycaster gets simpler - you dont need additional triangle data. Also is the geometric complexity with voxels a smaller issue than with polyongs. However, voxels of course remain cubes when looked closely; there triangles have an advantage.

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  5. thanks for your reply spacerat, but I was actually referring to SVO in combination with path tracing, which shoots a whole bunch of incoherent secondary rays around the scene to calculate global illumination. Do you have any ideas about that? Would it be faster to trace secondary rays in a voxel scene (using SVO) compared to a polygon scene?

    Sam

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  6. Thats a good question - I think thats dependent on the scene. If you're having a low poly-scene and the same scene voxelized, I would guess polygons turn out to be faster, as the tree-hierarchy is more shallow. For very dense and complex triangle meshes, voxels will be superior I guess. But without running experiments its hard to tell.

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  7. I was thinking the same. I think voxels will make a lot of sense in offline Hollywood-grade CG, when you have to calculate raytraced GI in a massive scene (equivalent of 500 M triangles and more).

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  8. Well, it just happened that I accidentially figured out that voxels were used in the Avatar movie. The VFX supervisor of ILM was telling about that in an interview.

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  9. Very nice work!
    Do you know this technology ?
    http://unlimiteddetailtechnology.com/

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