Questions tagged [pbr]

Physically-based rendering (PBR), sometimes referred to as physically-based materials or physically-based shading, is a 3D graphics rendering process that attempts to produce realistic images by accurately modeling light-matter interaction. Use this tag for questions about physically-based rendering, including shading, lighting, and materials.

Physically-based rendering (PBR), sometimes referred to as physically-based materials or physically-based shading, is a 3D graphics rendering process that attempts to produce realistic images by accurately modeling light-matter interaction. Different rendering engines may employ different methods and use different input parameters to target this goal.

Information

Examples

Parameters

Most PBR systems include some means to set how rough a surface is, and how metallic a surface is. One parameter may have multiple effects, for example increasing the roughness may blur the reflection map and spread out the specular highlight at the same time. This example image is a composite of outputs from the OSGJS PBR demo linked above:

Samples of PBR roughness and metallic-ness

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How to implement a metallic workflow in PBR?

there is a lot of material out there on the Cook-Torrance BRDF as well as on the Lambert BRDF. Real Shading in Unreal Engine 4 and Moving Frostbite to BPR give an in-depth explanation how to implement them for real-time rendering. What they omit is…
Henkk
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How is BRDF usually implemented?

I have a small path tracer, and I am trying to figure out how to implement some basic BRDFs. Here's a brief description of the pipeline I use (without recursion): 1) For each pixel: 1.1) For each sample: 1.1.1) I construct a path. …
Denis
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Frostbite PBR: different compression on separate texture channels of the same texture

Is it possible, and if yes how would it be possible, to create and read a RGBA Texture with different compression algorithms on separate channels in OpenGL4.x: Example A without real meaning: RG channels stores a normal map encoded in 3Dc B channel…
James Takarashy
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SceneKit: how to reproduce iOS 9 lighting color effect (one directional, one ambient) on iOS 10 without disabling PBR?

As this thread on the Apple forums mentions, lights on iOS 10 are now weaker and change how scenes look. The thread suggests setting SCNDisableLinearSpaceRendering to YES, but this did not work. Put another way, using SCNDisableLinearSpaceRendering…
Crashalot
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How to calculate specular contribution in PBR?

I'm trying to implement physically-based rendering (PBR) in our project (we started a small game engine for academic and learning purposes) and I cannot understand what is the right way to calculate specular and diffuse contribution based on…
TheCrafter
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Unity PBR Shader not showing up on Sphere

I am using HDRP. I have this PBR Shader Graph: But the result I get is this: The Shader is not showing up on the sphere at all.
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SceneKit view renders as phong instead of physically based materials

I have several objects in my scene, all of which had the "lighting model" of their material set to be physically based. When I run the app, the view I get looks nothing like the scene editor - it instead looks more like Phong materials. Is there a…
DanN
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USDZ File Black on Older Devices and Normal Map artefacts

I'm stuck creating USDZ files. I've issues with older devices, basically anything older than the iPhone X, displaying items with artefacts resulting from normal maps and other issues whereby the item appears entirely black. iPhone X and iPad on ios…
Allen Wixted
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Physically Based Rendering: role of ambient light in BRDF

I'm trying to figure out if my BRDF approach is correct or not. // Calculate sun BRDF color vec3 sunBrdf = brdf(tsLightSourceDir, tsEyeDir, tsNormal, vtsTangent, vtsBinormal, albedo.rgb, …
James Takarashy
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PBR GGX specular desaturated color

I am trying to implement PBR renderer. My specular highlight has desaturated color (especially in grazing angles) and escapes my light volume bounding sphere. Why is this happening? The function I use to calculate GGX specular: vec3…
Matej Kormuth
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How to deal with blow up of the GGX distribution term in PBR?

I'm working on learning PBR and Unity standard shader. The really large result from the GGX distribution term confused me. Unity standard shader uses GGX distribution term: // I re-write it into C# private float GGXTerm(float NdotH, float…
T3-Tan
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PBR lighting is broken with a ambiant light, not with a directionnal light

I have a problem with our ThreeJS PBR. I have created a simple threeJS on ThreeJS Editor project with two cubes where I set a PBR material on both cube with the following textures: My ORM map used in the OA map, used for the metalic map, and the…
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Why shadows are not rendered when PBR directional light is applied?

I've got a problem with rendering hard shadows in a PBR pipeline. I believe there is something wrong with PBR calculations because with a Blinn-Phong lighting model everything looks fine. These are lightning calculations - basic PBR struct…
BrodaJarek3
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PBR shader is too transparent

I have this shader: And this is the result: How can I make the grass less transparent, I swaped over from HDRP to URP and there is only PBR shader i know how to use.
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Aframe 1.0.4 - setting scene.environment does not update materials

So I saw an old post here: https://discourse.threejs.org/t/is-there-a-way-to-increase-scene-environment-map-exposure-without-affecting-unlit-materials/13458/4 That says... "If you apply the env map to Scene.environment, it is automatically used as…
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