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Questions tagged [pbr]

Physically Based Rendering is an approach that aims to ground the drawing of computer-generated scenes in the physics of light reflection and scattering and measurable properties of real-world materials, to give a more visually convincing effect that's consistent under a wide range of illumination and viewing conditions.

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How can I override the directional light processed by a shader?

I'm building a solar system and have made the simplifying assumption that the sun will always be at 0,0,0. Rather than worry about "real" lighting, my planet shader just works out where it ...
Basic's user avatar
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1 answer
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Is there a PBR-like material system for audio?

With visual/rendering materials, a very popular system for this is PBR. Materials made using PBR may define properties like albedo color, normal maps, emission, roughness, metallic, specular, etc. ...
Aaron Franke's user avatar
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Is there a technique to properly illuminate a PBR material when using directional light?

I use the following formula to calculate PBR color for each light source. For the sake of this post, let's assume that there is only one directional light. I am using Vulkan; so, +Y is "down"...
Gasim's user avatar
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How does Physical Based Shading work with multiple light sources?

I have implemented a PBR shader in my game engine that works with a single light source. Everything is good and made sense at a higher level about what each algorithm does. Now I am working on adding ...
Gasim's user avatar
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PBR GLSL shader incorrect lighting. Half being shaded

I have been following the tutorial at LearnopenGL to implement physically based rendering into my Vulkan game engine, and have gotten the following incorrect lighting results: The light is overhead, ...
Dylan Gentile's user avatar
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1 answer
145 views

How do you simulate UV light and materials with UV-reflective/fluorescent properties within a PBR renderer?

I have a PBR setup, say, in Unity (or Unreal, doesn't really matter, I'm asking about the general principle, not specific implementation), and I would like to add a UV light source, and have control ...
sh code's user avatar
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Cuda API to render using Physically Based Rendering (PBR) in OpenGL-ES based project

I need to develop a OpenGL-ES based application to render a model using Physically based Rendering (PBR). Do I need to use Cuda API to render the computation intense PBR rendering? Is there any ...
Arun AC's user avatar
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Why does my PBR material appear grey in game?

I am playing around with PBR materials and I cant get them to work correctly. When I create a material using PBR the model appears gray in game. Any ideas on why I’m not getting the same result? ...
Jason Crosby's user avatar
1 vote
1 answer
606 views

Performing image based lighting in an open world game

I finally have a PBR implementation in an engine that I'm writing for a game I'm developing but I'm stuck on how to use IBL in real situations. Most IBL tutorials use it just to show a single mesh or ...
Sammi3's user avatar
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Handling metallic roughness maps colour channels

I'm trying to use a metalness/roughness workflow and I'm not sure how to translate the colour channels into the different metalness and roughness attributes. I'm not sure if there's a standard on how ...
Sammi3's user avatar
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2 votes
1 answer
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How to write a PBR Unlit Shader in Unity? [closed]

I have a REALLY specific case here: I have an Texture (a webcam), that is used by a shader to pickup a few x,y colors at the cordinates, and renders to a ...
Ivan Seidel's user avatar
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1 answer
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What's the use and difference between Forward, Deferred and Physically Based Rendering?

Maybe I'm still confused about my own understanding, Forward Render: render the lighting of an object according to the light source in the scene. (e.g Phong) Deferred Render : render the scene to ...
raisa_'s user avatar
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3 answers
5k views

What's the difference between Raytracing and Physically-based-rendering?

I know raytracing is a technique based on the route calculation done by the light, following the rays through the interaction with the surfaces, and that Pbr is a collection of render techniques that ...
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314 views

Basic equation for pure metallic reflectance

I'm working on a live wallpaper that shows a pure metallic object. Since it's a live wallpaper, I can make a ton of approximations...this isn't a full blown scene in a game world. My shader only has ...
TenFour04's user avatar
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Artifacts when trying to implement Cook-Torrance BRDF

I am trying to implement the Cook-Torrance BRDF within OpenGL, but I keep running into issues. The most obvious one are black patches and a bright spot at (0, 0). I checked my shader multiple times, ...
MKII's user avatar
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BRDF Incorrect specular highlights

I'm currently attempting to implement BRDF lighting, and am hitting a bit of a snag with my specular term - the specular highlights aren't rendering correctly. To make things simple, I'm using a ...
Yattabyte's user avatar
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2 votes
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Eye Parallax Refraction Shader

I am trying to implement the Parallax Refraction effect explained by Jorge Jimenez on this presentation: http://www.iryoku.com/downloads/Next-Generation-Character-Rendering-v6.pptx and I am facing ...
MaT's user avatar
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4 votes
1 answer
900 views

Physically based shading - ambient/indirect lighting

I implemented a physically based path tracer after studying PBRT by M. Pharr and G. Humphreys. Now I'm trying to apply physically based rendering to real time graphics using OpenGL. I want to start ...
Fabrizio Duroni's user avatar
2 votes
1 answer
619 views

Disney BRDF - where is metallic factor input into BRDF?

Burley states about metallic parameter: "This is a linear blend between two different models. ..." What are the two models? I can't see this described in the Frostbite or the Unreal papers either. ...
Justicle's user avatar
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IBL probe BRDF pre-integration artifacts

I'm following 'Moving Frostbite to PBR course notes' to implement IBL in my rendering engine in OpenGL but I'm having some trouble pre-integrating the specular component of the equation. As you'll ...
zeb's user avatar
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2 votes
1 answer
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How do I calculate specular contribution in physically-based rendering?

I'm trying to implement physically-based rendering, in a small game engine built for academic and learning purposes. I cannot understand the right way to calculate specular and diffuse contribution, ...
TheCrafter's user avatar
2 votes
1 answer
7k views

Schlick Fresnel Shader

I hope you are all doing ok. I have an issue with my Fresnel shader that doesn't allow the Fresnel to change as my camera moves around. I'm not sure what i'm doing wrong. I'm using glsl with the ...
Richmar1's user avatar
3 votes
0 answers
405 views

Physically-based BRDFs

I'm starting to implement a real-time PBR shading pipeline in one of my projects and had a few questions that I thought folks around here could help clarify. 1) Is it fair to say that in a PBR ...
mike's user avatar
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SVD vs Normal decomposition for BRDF compression

In the slides over here by NVidia, they describe methods for BRDF compression. They first create a BRDF matrix where each column(or row) corresponds to a single light direction (or outgoing view ...
Muhammad Omer's user avatar
3 votes
1 answer
135 views

Ray tracing - BRDF using Cornell measured spectral data

I wrote a ray tracer that implements various BRDF models (Oren Nayar, Lamber, Torrance Sparrow and so on). Now I'm trying to implement a BRDF from measured data. I choose the Cornell database data ...
Fabrizio Duroni's user avatar
14 votes
2 answers
30k views

What is the difference between PBR and SSR?

I am very new to game development and I have been trying to understand the difference between Screen Space Reflection and Physically Based Rendering. I have read about PBR, and from what I understand,...
Kumaresan Sandran's user avatar
1 vote
1 answer
163 views

Specular intensity of non-metals(plastics) in metalness pbs workflow

The specular color in metalness/roughness workflow is usually defined as following: float3 specColor = lerp(0.03f, albedoColor, metallic); The Cook-Torrance BRDF ...
Ilya Suzdalnitski's user avatar
1 vote
2 answers
594 views

PBR Metalness Implementation: specColor at Value 1?

I am doing a BRDF supporting the metalness/roughness workflow. I know that in cases of Metalness = 1.0 the reflectance value is taken from the albedo map - so is the specular color to tint the ...
Jens Kafitz's user avatar
3 votes
2 answers
972 views

Rectangular area light illuminance - colour banding

I'm currently working on an implementation of rectangular area lights but I am having some issues with the illuminance calculation, which gives me serious colour banding across the entire lit area. I'...
Bentebent's user avatar
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2 votes
2 answers
1k views

Does PBR mean only one, right technique to view 3D scenes?

For example if I call Unity 5's render pipeline "PBR" (Physically-Based Rendering) and also call Unreal Engine 4's render pipeline "PBR," does it mean that the same model with the same PB textures ...
komorra's user avatar
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2 answers
3k views

What are 'physically-based' lighting/rendering/materials?

What's the difference between physically based lighting, physically based rendering and physically based materials? How they are different from deferred and forward rendering? And physically based ...
Inder Gill's user avatar
1 vote
1 answer
1k views

How does an energy-conservative Blinn-Phong-Fresnel model work?

What is a plausible, basic equation/pseudo-code for energy-conservative Blinn-Phong shading, including Fresnel with a coloured light-source? The net gives so many alternatives that it's hard to ...
Viktor Sehr's user avatar
2 votes
2 answers
4k views

GGX energy conservation

I´m trying to implement a microfacet BDRF with GGX density function in my renderer. I have read almost all the papers out there in the last week, and I have a bunch of equations that should work fine, ...
Sikowsky's user avatar
5 votes
1 answer
2k views

Using textureGrad for anisotropic integration approximation

I'm trying to develop a real time rendering method using real time acquired envmap (cubemap) for lightning. This implies that my envmap can change as often as every frame and I therefore cannot use ...
Amxx's user avatar
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5 votes
1 answer
5k views

GGX specular BRDF is way over 1!

Now, the classic Torrance derivation for roughened surfaces which Cook took into vectorized form yields the familiar parametrization of a specular BRDF where we have the NDF which decides how much ...
CloseReflector's user avatar
10 votes
2 answers
4k views

What is physically correct lighting all about?

I can't find anything comprehensive using Google. I'm wondering what the core concepts of physically correct lighting are, and where I could read up on it. What's physically correct lighting all about?...
TravisG's user avatar
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5 votes
2 answers
868 views

Microfacet model - BRDF obtain extreme values at grazing angles

I've been trying to replicate the result of this paper (linked directly to PDF paper, but you don't need to read it to give an answer) and encountered a problem with the BRDF according to the ...
Nhan Nguyen's user avatar
4 votes
1 answer
1k views

Matcap and BRDF Shading

I just would like to know what's the difference between the Matcap shaders used in ZBrush for example and the Bidirectional Radiance Distribution Function shader. Are there two techniques the same ? ...
MaT's user avatar
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5 votes
1 answer
1k views

Where can I find a BRDF reference implementation?

Does anyone have a link to a sample implementation of how to create/handle 4D BRDFs? I found a few interesting papers and websites, Szymon's (student, Princeton) BRDF survey, 1997 SIGGRAPH survey ...
bobobobo's user avatar
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