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Is there a more extensive collection of OpenGL materials? [closed]

I develop a modeling program where users can choose from a set of predetermined OpenGL materials or enter their own custom materials. I would like to expand the list of predetermined materials ...
Rob McDonald's user avatar
1 vote
0 answers
57 views

Is there a name for the values of a material at a point?

As I understand it, the usual concept of a “material” in computer graphics, particularly 3D modeling, is a set of parameters (for example, color, specular reflectivity, IOR, light emission, etc.), ...
Kevin Reid's user avatar
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1 vote
0 answers
41 views

ThreeJS multicolor material

How can I have a multicolor material in ThreeJS? I'm looking for a way to have a single material and use one or more b/w masks to color the surface of the model with the same amount of colors; the ...
fudo's user avatar
  • 121
2 votes
2 answers
83 views

Examples of anisotropic surfaces

Being faced with a design choice, I have to decide between supporting anisotropic surfaces or not in my ray tracer. Is there any common use case of this feature other than velvet (so that I may be ...
Ujjwal Rajput's user avatar
0 votes
1 answer
629 views

Converting from RGB Color Picker to Surface Reflectance

I am trying to derive the material reflectance values from a color picker tool(say MS Paint). My understanding is to first gamma decode(raise to the power of 2.2) the RGB values from the color picker, ...
ali's user avatar
  • 740
0 votes
1 answer
684 views

How to read illum value from mtl file using Assimp library?

I am loading an OBJ file using the ASSIMP library. Following is the MTL file associated with the obj file. ...
user13184's user avatar
3 votes
1 answer
221 views

What is a "light source" in global illumination?

In the context of global illumination and the scattering equation, do we need to understand "light sources" as surfaces with a "purely emissive" material on which no scattering is present? In ...
0xbadf00d's user avatar
  • 203
0 votes
1 answer
130 views

Microfacet BRDF artifacts

I've been trying to implement a microfacet specular BRDF based on the equations in Real Shading in UE4, but I'm getting weird ring-shaped artifacts in the highlights of rough surfaces: Here's the ...
Sam's user avatar
  • 198
1 vote
0 answers
84 views

Questions about BRDF parameterization

Hi I'm trying to get a better understanding of the BRDF modeling. I only implemented naive diffuse(lambert), specular and microfacet BRDF before, but I don't have much experience in mixed BRDFs and ...
AccM's user avatar
  • 61
3 votes
1 answer
805 views

Iridescence/Thin-film interference integration as a layer

I'm trying to integrate the thin-film interference effect described in the paper "Belcour, L., & Barla, P. (2017). A practical extension to microfacet theory for the modeling of varying ...
avilapa's user avatar
  • 53
2 votes
1 answer
263 views

Confused on reflection coeffcient of Fresnel equations

I am reading a paper about layered materials. However, I am confused on the implementation of this paper. The following picture describe the layered material. r_ab is a complex reflection coeffcient ...
TIANLUN ZHU's user avatar
12 votes
2 answers
855 views

Why does graphics speak of "dielectrics" rather than insulators?

For example, Filament's documentation at https://google.github.io/filament/Filament.md.html uses the term "dielectrics" when contrasting nonconductors to conductors, which it calls "metallics". And ...
learning graphics's user avatar
1 vote
1 answer
463 views

Understanding material .mtl files

I am reading this piece of documentation to understand mtl files So far I am stuck trying to understand the difference between ambient, diffuse and specular reflectivity (Ka, Kd, Ks). If I am ...
Makogan's user avatar
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1 vote
0 answers
40 views

Proper design of data structure to store wavefront file information?

Currently I have a naive Mesh data structure to store wavefront files. This data has 3 buffers for the vertices, normals and UVs. It works well to the point I can render the sponza scene, despite ...
Makogan's user avatar
  • 1,726
2 votes
1 answer
661 views

Combine material coefficients and textures in Phong Shading

I'm trying to implement a simple Phong shader that supports non-physically-based materials and textures. Even though the material has a texture for each light component I still want the respective ...
Daniel Marques's user avatar
1 vote
1 answer
1k views

How can I implement this BSDF?

I am trying to implement a path tracer, but I have some problem. The class Spectrum is color. I implemented a mirror material like this: ...
bin guo's user avatar
  • 31
2 votes
1 answer
140 views

Confused about material layering

I am a little bit confused about the various flavors of material layering in both online and offline rendering. I had naively assumed (after using the Mix Shader in Cycles and a few minutes in ...
user avatar
10 votes
4 answers
27k 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?
chaosink's user avatar
  • 591
3 votes
0 answers
290 views

Beer's law in dielectric material

I am trying to implement Beer's law according to this page in dielectric material but I am not sure have done it correctly as the image does not suggest so. The formula is: I(s) = I(0) * pow(e, ln(A)*...
ali's user avatar
  • 740
2 votes
0 answers
54 views

Would the surface of a large carbon-nanotupe structure look metalic?

CNT is a promising new material, which Wikipedia describes as such: Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. These cylindrical carbon molecules have unusual ...
Nikolaj's user avatar
  • 121
4 votes
1 answer
1k views

Loading a material via assimp

I'm writing a raytracer and I'm using the assimp library to load objects. I have an object's material specified in a .mtl file: ...
Michal Kučera's user avatar
6 votes
1 answer
1k views

How can a diffused(frosted) glass be modelled in path tracing

How can a diffused(frosted) glass be modelled in path tracing? Currently I am able to define a window poly line as a clear glass material where it transmits or reflects the ray. I am not clear though ...
ali's user avatar
  • 740
2 votes
0 answers
448 views

Is there a material table for the Cook Torrance BRDF?

Is there a material table that lists all the specific values to obtain a certain type of material (e.g: copper or asphalt) available? I found this table in the paper: A Reflectance Model for ...
Arjan Singh's user avatar
  • 2,511
3 votes
2 answers
2k views

Phong: Real-time rendering of Metal and Plastic Materials

Using a shader that works like Phong, what would be the difference between painted Metal and plastic? I seem to remember reading in books years ago, that I no longer have access to, the following: ...
Invariant's user avatar
  • 133
11 votes
1 answer
1k views

Path tracer - multi layered materials and importance sampling

I'm currently trying to implement a Monte Carlo path tracer. I've done some research and it seems that a common approach to materials is to use a layered model. Something like this: When light hits ...
castan's user avatar
  • 113
7 votes
1 answer
2k views

Mimicking Blender's "roughness" in my path tracer

Recently I asked a question regarding how to mix a glossy and diffuse shader in my path tracer: Mix shader looks wrong on my path tracer. I thought it was incorrect, but a comparison between mine and ...
Henry Bergin's user avatar
7 votes
1 answer
610 views

What is the most physically accurate model of surface materials possible in computer graphics?

I am looking for theoretical and implemented models to represent surface materials in software that strives for physical accuracy. Is BRDF really the best model? What alternatives are better? Why? ...
Mr. Developerdude's user avatar
4 votes
1 answer
86 views

Is there a material that contributes to GI, but isn't directly visible?

I am doing renders of the inside of a room. I would like to show a "bird's eye" view of the room, from above the ceiling (outside the room), but still see the interior of the room. An easy way of ...
aaaidan's user avatar
  • 143
4 votes
1 answer
325 views

Material Layering

So after reading this Unreal Engine 4 Documentation page: https://docs.unrealengine.com/latest/INT/Engine/Rendering/Materials/LayeredMaterials/ (Which describes how to use material layering in UE4) ...
Arjan Singh's user avatar
  • 2,511
1 vote
0 answers
90 views

Alias|Wavefront .mtl File "decal" Command

There are material color and texture colors (e.g. Kd 0.8 0.8 0.8 vs. map_Kd diff.png). The documentation says of this: ...
geometrian's user avatar
  • 1,990
5 votes
1 answer
164 views

Does light particle loses energy when it hits something?

I have some material which I want to represent as a collection of spheres (atoms) and a particle of light (photon). I'm firing this particle and checking for the collision against atoms. What should ...
nikitablack's user avatar
17 votes
2 answers
3k views

Why do most photorealistic renderers have similar material test scenes?

I notice that most photorealistic renderers have very similar material test scenes. Here are a few examples: Blender Mitsuba Vray My question is: why is this specific model / style chosen to test ...
ap_'s user avatar
  • 2,214