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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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Unity 2019 Extremely Reflective Foliage

I've been working on a project involving a lot of foliage and I needed translucency so I upgraded to the latest unity beta to get access to the new features and the HDRP (which is still available on ...
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1answer
79 views

How to write a PBR Unlit Shader in Unity?

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 ...
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40 views

is that a pbr Shader?

im not sure about one thing: In my engine i have a shader wich takes: Diffuse, Specular, Normal, Metallic, Roughtness, Refraction,Height, Detail and Emission maps. The lighting is calculated using ...
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393 views

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 ...
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3answers
786 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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47 views

Is there another to blur a cubemap other than changing mip level for PBR?

I am working on a physically based shader and have encountered a problem of high mip levels not properly blurring environmental maps. At first I've tried to linearly interpolate between two mip ...
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1answer
95 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 ...
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1answer
156 views

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, ...
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168 views

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 ...
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1answer
616 views

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 ...
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1answer
452 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 ...
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1answer
234 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. ...
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248 views

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 ...
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1answer
354 views

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, ...
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1answer
4k 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 ...
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0answers
315 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 ...
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1answer
90 views

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 ...
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1answer
112 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 ...
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2answers
16k 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,...
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1answer
123 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 ...
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2answers
522 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 ...
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2answers
788 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'...
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2answers
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 ...
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2answers
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 ...
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1answer
995 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 ...
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2answers
3k 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, ...
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1answer
1k 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 ...
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1answer
3k 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 ...
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2answers
3k 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?...
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1answer
584 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 ...
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1answer
971 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 ? ...
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1answer
975 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 ...