What is PBR?
Physically Based Rendering (PBR) is a method of shading and rendering that provides a more accurate representation of how light interacts with surfaces. It can be referred to as Physically Based Rendering (PBR) or Physically Based Shading (PBS). Depending on what aspect of the pipeline is being discussed, PBS is usually specific to shading concepts and PBR specific to rendering and lighting. However, both terms describe on a whole, the process of representing assets from a physically accurate standpoint. - Wes McDermott, Allegorithmic PBR Guide, Vol. 2
The purpose of this article is to guide you through Sketchfab's implementation of PBR, not to teach you how to use PBR. There are many great resources on PBR theory and practice, including Allegorithmic's PBR Guide.
PBR on Sketchfab
You can switch between Classic and PBR rendering in Scene Settings. By default, uploads are set to PBR mode. This is almost always the best choice. It provides more realistic material and lighting, and does not prevent anything that could be done in a Classic workflow. Shading must be Lit for PBR lighting and reflections to work. Using an Environment to light the scene is typically the best option. See Lighting.
The PBR material tools are available in 3D Settings.
- From your model, go to Settings → 3D Settings or add "/edit" to the end of any model URL.
- Select the Materials panel in the top left.
See also Materials and Textures.
- PBR Maps
- Roughness / Glossiness
- Normal / Bump
- Ambient Occlusion (AO)
- Faces Rendering
PBR has two main workflow options: Metalness and Specular.
The channels specific to Metal/Roughness are Base Color, Metalness, and Specular F0.
- Base Color: an (s)RGB texture or solid color for reflected color (non-metals a.k.a. 'dielectrics') or reflectance values (metals)
- Metalness: a linear grayscale texture; black (0.0) for non-metal and white (1.0) for raw metal
- Specular F0: a linear grayscale texture for Fresnel values (non-metals)
The channels specific to Specular/Glossiness are Albedo and Specular.
- Albedo: an (s)RGB texture or solid color, without reflectance values
- Specular: an (s)RGB texture or solid color for reflectance values (metals, color) and F0 (non-metals, grayscale)
Roughness / Glossiness
A linear grayscale texture, or a solid grayscale color, for describing surface irregularities. See Diffuse vs Specular Reflections.
A grayscale depth map to displace a model's vertices. The model must be subdivided as needed before uploading because we cannot generate new vertices in real time.
Normal / Bump Map
A texture to add bumps and dents. Enable Invert Y to reverse the bumps and dents. Its usage is the same in PBR and Classic. See also Tangent Space and Normal Maps.
Ambient Occlusion (AO)
A texture to define large areas of occluded light. Usually, AO only affects the diffuse light contribution. You can enable Occlude specular to also occlude the specular contribution (reflections). It is similar to Lightmap in Classic.
A texture to define small areas of occluded light. It does not exist in Classic.
Sketchfab supports several transparency modes: Blending, Additive, Dithered, and Mask. Its usage is the same in PBR and Classic.
See Transparency for details.
A texture or a solid color to make the material glow. Its usage is the same in PBR and Classic.
You can switch between rendering both sides of a material surface or just the front face. Single-sided rendering (back-face culling) is often a good choice for 3D scans. It can also help performance. Other applications include Cel Shading and Cartoon Outlines. Its usage is the same in PBR and Classic.
Once you've made your adjustments, including position and orientation, be sure to update your model's thumbnail image and default position with Save View and/or save your changes with Save Settings. You can return to your model by clicking either the model's name or Exit.
Have more questions? Submit a request