Computer Graphics Stack Exchange
Computer Graphics Stack Exchange

Questions tagged [material]

31 questions
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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 materials? Does it have some advantage over…
ap_
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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 here on stackexchange,…
learning graphics
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11
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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 the surface, Fresnel tells us how much of that…
castan
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9
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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
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7
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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? What drawbacks beside performance do these models…
Lennart Rolland
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6
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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 how it should work if the sheet of glass is…
ali
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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 Blender's seems correct. However, now I am lost…
Henry Bergin
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5
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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 happen if collision occurs? I see two possible…
nikitablack
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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: newmtl rightSphere Ka 0.01 0.01 0.01 Kd 0.01 0.01 0.01 Ks 0.30 0.30 0.30 Tf 0.10 0.10 0.10 Ns 200 Ni 2.5 illum 7 and I'm…
Michal Kučera
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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 doing this is to simply hide or remove the ceiling…
aaaidan
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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) I wanted to know how material layering is…
Arjan Singh
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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 contrast, any surface in the scene geometry could be…
0xbadf00d
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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 iridescence."…
avilapa
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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)*s) 'A' is said to be transmission coefficient…
ali
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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: Specular color for painted metal is same color as…
Invariant
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