Questions tagged [pbr]
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87 questions
2 votes
1 answer
83 views
How do you derive the integral equation of transfer in the PBRT book?
In the PBRT book section on the equation of transfer, they give the equation $\frac{\partial}{\partial t}L_o(p',\omega) = -\sigma_t(p',\omega)L_i(p',-\omega)+\sigma_t(p',\omega)L_s(p',\omega)$, and ...
- 87
0 votes
0 answers
49 views
What is the underlying cause of this phenomenon encountered when implementing IBL?
I implemented the entire IBL pipeline using Microsoft's MiniEngine framework, but the specular highlights are not smooth enough in the end. ...
- 31
1 vote
1 answer
85 views
How is this null-scattering transmittance equation in PBRT derived?
In the PBRT book section on null scattering, they define the null-scattering coefficient $\sigma_n$ and the constant majorant $\sigma_{maj}$, and define the equation: $\frac{dL_o(p, \omega)}{dt} = -(\...
- 87
1 vote
1 answer
239 views
How to make ambient light look good (without Global Illumination)?
I recently added Voxel Cone Tracing Global Illumination into my game engine and everything works great. But I need somehow improve my plain ambient lighting without VXGI. Are there any techniques? I ...
- 23
1 vote
1 answer
94 views
Why is "Entreprise PBR 2025" from Dassault using 1.0f - max(Fr(V, N), Fr(L, N)) for the Fresnel transmission instead of just 1.0f - Fr(L, N)?
Dassault Systèmes has a spec for their PBR material: Enterprise PBR 2025 I rewrite Eq. 72 for clarity: ...
- 301
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
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