Questions tagged [brdf]
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150 questions
1 vote
1 answer
64 views
Question of different BSSRDF form
I'm learning BSSRDF but I'm so confused about the different forms of the diffusion profile approximation. In this SIGGRAPH 2013 talk: BSSRDF Importance Sampling. They seem to let the BSSRDF directly ...
- 69
1 vote
1 answer
118 views
Explicit Light Sampling: Where does $n \cdot l$ come from?
In these lecture notes: http://www.cs.utoronto.ca/~strider/docs/D18_DistributionRayTracing.pdf on page number 140 (as labelled on the PDF), it says that if we perform explicit light sampling, the ...
- 113
2 votes
1 answer
91 views
The reciprocity of BSDF and equilibrium of rendered scene
in chapter 6 of Eric Veach's paper, Veach has proved general reciprocity of BSDF by Kirchhoff’s equilibrium radiance law and detailed balance $$ \frac{f_s(w_i \rightarrow w_o)}{\eta_o^2} = \frac{f_s(...
- 23
2 votes
1 answer
659 views
Confusion over Microfacet-based BRDFs and Normal Distribution Functions
Through reading various sources online, I've become a bit confused. I'll briefly outline what I think I do understand: My understanding is that microfacet-based BRDFs assume there is always a perfect ...
- 319
1 vote
1 answer
184 views
Fixing bias in Specular lobe
Im currently making some modifications for a path tracer for Minecraft, specifically adding glossy refractions. The program currently uses for specular reflections this method, linear interpolation ...
1 vote
3 answers
391 views
How to calculate the radiance of the reflected light ray using the Blin Phong BRDF
to get the radiance of the Lambertian diffuse reflected light, I have to multiply the constant pdf (rho/pi) with the incoming intensity I0*cos(theta_i), where cos(theta_i) is given by the scalar ...
- 11
0 votes
1 answer
384 views
Does fresnel reflection make sense for metals?
I am implementing fresnel reflections for materials in my renderer. Does it make sense for metals? Here my implementation: ...
- 105
1 vote
1 answer
317 views
Importance sampling in a path tracer
So, I'm attempting to implement a monte carlo path tracer that uses the ggx brdf model. However, I'm rather confused about how to sample the light direction. I know that theta and phi can be sampled ...
- 13