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I took a quick run through the comments in the BDPT integrator but couldn't determine if you have implemented Georgiev's VCM or Hachisuka's near-equivalent. I'm under the impression that these are really important contributions. Are they included? Will they be? How about Markov Chain Monte Carlo? Wi...

soren renner wrote:

i have no clue what it is i'm seeing

I am familiar with this sort of comment. Unfortunately there is no help for your condition, which is intractable.

Perhaps a few rounds of MineCraft would help?

First of all, are you using the common form of the Fresnel equations that assumes lossless media, or are you using complex numbers for refractive index? If you are only using real numbers, then you cannot model anything that absorbs light, such as opaque plastic. Second, the appropriate way to combi...

For papers on the ABC BSDF you will have to step outside of the computer graphics world and into optical engineering. A good reference book that discusses the ABC (or K-correlation) BSDF is John A. Stover, "Optical Scattering: Measurement and Analysis", 2nd ed. SPIE Press (1995), Section 4.5 (other ...

@dr_eck: I haven't tested the ABC model yet. The main reason is that I need a BRDF model with easily indentifiable parameters for the end-user to control. The microfacet is easy to control with its unique roughness parameter. So far, I haven't been able to make the A, B, and C parameters intuitive ...

@ingenious: Are you volunteering to take the lead on that?

@ypoissant: In both the ABC and the ABg BRDFs the A coefficient is set so that the integral of the BRDF is equal to the total integrated scatter (total reflectance), so both of these conserve energy. This is required for illumination engineering, which is their main field of application. I assume th...

@ypoissant An albedo of >20 sounds crazy, but if your model is wrong and you are computing BTDF near the critical angle, I suppose it could happen. Lots of wierd things happen near the critical angle. The literature, especially the Harvey-Krywonos paper should help you figure this out.

Sorry for being late to the party. As I was saving the paper by Xu to my BRDF file, I discovered a copy of his dissertation. It has no copyright notice, so I don't see any reason I can't send you a copy if you PM me. On another tangent, it is very important to note that the microfacet model is tied ...

It seems to me from your reply that a first approach would be to model for example a part of a sphere - trace a refraction ray trough it and then trace the resulting ray into my scene? Yes, that will work. If your lens is a sphere on 1 side and a plane on the other, thickest in the middle, then it ...