Questions tagged [material]
The material tag has no usage guidance.
30 questions
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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.), ...
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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 ...
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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 ...
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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, ...
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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.
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
- 1,831
2
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687
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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 ...
- 163
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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:
...
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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 ...
user3412
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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?
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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)*...
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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 ...
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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:
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- 353
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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 ...
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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:
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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 ...
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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 ...
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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? ...
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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 ...
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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)
...
- 2,491
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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:
...
- 2,030
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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 ...
- 731
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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 ...
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