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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
0 votes
0 answers
179 views

One-sample model Multiple Importance Sampling with balance heuristic

Recently I feel a bit confused about one-sample model MIS. One sample model MIS can be found here in Veach 1997. 9.2.4 The one-sample model, and this one-sample model is widely used in the opensource ...
Enigmatisms's user avatar
  • 1,112
0 votes
2 answers
495 views

PBR : Understanding importance sampling

I have read this article On PBR and in it we have NDF function defined as follows Then I have read this article on random vector generation Here are what I feel are the important bits. Now jump to ...
Sync it's user avatar
  • 179
1 vote
1 answer
2k views

Can't understand the Importance sampling GGX

I've read many articles relating to importance sampling of GGX. However, I still feel confused. The formula of GGX is : And many article says we should use this formula to sample: In the formula, ...
TIANLUN ZHU's user avatar
3 votes
1 answer
475 views

Importance Sampling in Unreal Engine Formula Derivation (Irradiance term)

I am currently trying to understand IBL in Unreal Engine, and there are so much things that I don't understand about the formula. Unreal approximate the specular term of shading equation by doing ...
kevinyu's user avatar
  • 493
1 vote
0 answers
148 views

How to make Convolved Diffuse and Specular image in C#

I am trying to take either a HDR panoramic or HDR cubeMap and from that create a Lambert Irradiance environment map and a Cook-Torrence Specular environment map. I am stuck at the proper ...
J.Chavez's user avatar