Global Illumination

anubis 101 Jan 18, 2005 at 11:39


the image shows a 20min rendering of my path tracer (rest in peace). you can see a diffuse sphere, a glass sphere with fake fresnel (notice the caustics though) and a purely specular sphere. all the light in the room is diffusely reflected.
allthough i was quite satisfied with the path tracer you can still notice some banding effects in the shadows due to bad recycling of the stratified light samples.
i used stratified samples for the path tracing as well, which actually gave a nice effect during image generation because the scene was sort of “scanned” from left to right by the pixels. the anti aliasing is done via jittered sampling of the rays.
an earlier version of the path tracer had support for traceing CSG surfaces rather efficently but i have no really interesting pictures of that on my machine (allthough i still have an article on the topic lying around, which i haven’t released so far but is completely finished).
i abandoned the path tracer though in favor of photon mapping based on the kd tree construction technique proposed in the “Faster Photon Mapping using the Voxel Volume Heuristic” paper on you can expect to see nice pictures rendered by the photon mapper soon :)

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dk 158 Jan 18, 2005 at 16:47

awsome work! I bet there’s room for optimizations to reduce that 20min rendering time.
I’d be interested in reading your paper.

anubis 101 Jan 18, 2005 at 17:58

well… for one it’s path tracing and that is only getting so fast. once i have the photon mapping finished i expect things to be much faster.

bladder 101 Jan 19, 2005 at 03:55

sweet picture. I should really start getting into this “one hour rendering” business. I wonder how long before this stuff becomes real time.

anubis 101 Jan 19, 2005 at 12:33

with photon mapping the map generation “only” takes a few seconds and the rendering can be done at least “interactive”. i’m pretty sure that dual core processors will bring the change here