All Questions
16
questions
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 ...
- 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 ...
- 229
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. ...
- 103
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:
...
- 103
0
votes
1
answer
207
views
total internal reflection implementation in pbrt-v3
I've been implementing a path tracer, referring pbrt-v3. However, I'm a bit confused about its implementation. Code is here.
It seems when we sample to do transmission, it tests if it meets a total ...
- 293
0
votes
0
answers
75
views
Cook-Torrance Specular BRDF Artifact [duplicate]
I am currently experiencing a very obvious artifact that occurs when looking at objects on very grazing angles
Here is a picture of the artifact:
I noticed that the issue was coming from my ...
- 51
1
vote
1
answer
419
views
Normal Artifacts On Grazing Angles
I am currently experiencing a very obvious artifact that occurs when looking at objects on very grazing angles
Here is a picture of the artifact:
I noticed that the issue was coming from my ...
- 51
5
votes
1
answer
2k
views
Phong and the Rendering Equation: What's with the cosine?
Ignoring emission and shadowing for simplicity, the rendering equation can be stripped down to:
$$L(x, \, \vec \omega) = \int_{\Omega}{f_r(x, \, \vec \omega^\prime, \, \vec \omega) \, (\vec \omega^\...
- 2,293
2
votes
0
answers
484
views
How to simulate specular reflection in Light Tracing?
I am implementing light tracing from this website.
The right wall on the below image is perfect mirror(specular reflection). Its BRDF returns zero that's why it's been rendered black. But how is it ...
- 740
10
votes
4
answers
28k
views
What is the difference between glossy and specular reflection?
What is the difference between glossy and specular reflection?
What is their relations with BRDF?
- 591
5
votes
1
answer
1k
views
Fresnel and specular colour
I'm trying to implement Cook-Torrance BRDF and had previously bookmarked this question as it looked very well thought out. Going through it, I'm confused about the Fresnel equation. The author has the ...
- 700
31
votes
2
answers
7k
views
Path tracing the Cook-Torrance BRDF
-- Sorry for the long post, but I prefer to do that way because "Devil is in the details." :)
I am writing a path tracer from the scratch and it is working nicely for perfectly diffuse (Lambertian) ...
user5681
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 ...
4
votes
1
answer
116
views
Data fitting SVBRDF with L-M
I am reading two shot svbrdf capture . I want to understand the data fitting.
For example, I have my input image 3000x2000 pixels, and I divide it to create my source tiles of 192x192 pixels. The way ...
- 149
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 ...
- 4,420