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2 votes
0 answers
129 views

"Charlie" Sheen BRDF's directional albedo integrates to values higher than 1 at low roughnesses. Does this mean it is not energy conserving?

I am implementing the BRDF from the 2017 paper "Production Friendly Microfacet Sheen BRDF". This BRDF is modelled as a coat layer stacked on top of a base specular. In order to do so in an ...
avilapa's user avatar
  • 53
1 vote
1 answer
247 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 ...
Chris Gnam's user avatar
0 votes
0 answers
63 views

Unable to compute fresnel reflections properly

I am implementing fresnel reflections for materials in my renderer. According to this source, here the look I should obtain when rendering a sphere over a grey background: I have two implementations. ...
StudenteChamp's user avatar
0 votes
1 answer
168 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: ...
StudenteChamp's user avatar
2 votes
3 answers
1k views

PBR : Understanding the right part of Split sum integration of specular IBL

This is the website I am learning from. In the specular part of IBL this is the split sum approximation Now the left part of the equation I have asked in This post and I have understood everything ...
Sync it's user avatar
  • 179
2 votes
1 answer
449 views

Bug: Overly Sharp Highlights in PBR

I'm still working on my BRDF equations. Theoretically, all equations are correct, but the hilights are super sharp. I'm not sure if this is a result of me not using Image-Based Lighting (I currently ...
Karim Abdel Hamid's user avatar
23 votes
2 answers
8k views

How to properly combine the diffuse and specular terms?

As far as I understand, in a BRDF the Fresnel term is telling us the probability for a photon to be reflected or refracted when it hits a surface. The reflected photons will contribute to the ...
Julien Guertault's user avatar
18 votes
2 answers
7k views

What is the accepted method of converting shininess to roughness, and vice versa?

Most modern renderers use physically-based materials and their models are often parameterized over roughness. Since this wasn't always the case with renderers, conventional assets often don't have a ...
ap_'s user avatar
  • 2,214