Introduction to PBR Materials
PBR is an acronym for Physically Based Rendering. It attempts to show the visuals in a way that mimics the flow of light in the real world by simulating how materials absorb and reflect light. Most recent game engines are increasingly using PBR textures due to their photorealistic effects. For real-time rendering, they are said to be the best approximation of real-world scenarios as this does not solely depend on the detailed 3D model which comes at a performance cost as the games lately have large amount of models. To create an effect, most render engines have their unique workflows. However, PBR textures create the same effects in different software. As a result, in addition to photorealistic quality, exporting your project to another software becomes simple.
PBR workflow supports the following map types if used in a combination as with the right properties can easily achieve the realistic visual.
- Albedo/Diffuse maps
Both of these maps have almost the same purpose. They give a material color. But as you can see in the image above, the diffuse map has additional information about shadows and highlights. While the albedo map has more average values of color brightness across the entire image. So It looks less contrasting.
2. Normal/Bump Maps
Both of these maps are used to add details onto a surface without using more polygons in a 3D model. Thanks to them, light falling on the surface changes its behavior, making false shadows and highlights from non-existing bumps and dents. It gives the impression that these bumps and dents exists, which allows you to save a lot on polygons.
3. Roughness
The Roughness map control the sharpness of the reflections on various parts of a material’s surface.
If you use a roughness map, the whiter a part of the texture, the more rough the part of the material, and thus the more diffuse the reflected light is.
4. Metalness
This map controls which parts of a surface are metal and which parts are not metal. White pixels are metal, black pixels are non-metal. Since materials in the world usually falls into two categories: dielectrics (Ceramic, Plastic, Mica, and Glass)and metals, a metal map mostly contains only completely black or white colors and rarely anything in between.
5. Displacement/Height Map
These are used to change an object’s geometry. It displace points of the geometry along normals of the surface. But often in order to see an acceptable result, you must have a dense mesh of this object.
The displacement maps are very costly on the memory if not used carefully and intelligently which can lead insane amount of render times.
6. Alpha/Opacity Map
This map controls which parts of a surface are transparent and which parts are not. The darker the pixels, the more transparent the surface, and vice versa.
7. Ambient Occlusion
If you want to add more shadows and pronounced details to your model, you can use an ambient occlusion map. This map is used in mixed multiplication mode with an albedo or diffuse map.
This map creates soft shadows that should naturally occur when indirect or ambient lighting is cast out onto your scene.
Experience the PBR Material Studio which to see the different material types in viewer.
The Blog focuses on educating the PBR workflow and explaining each map type under this pipeline at an introductory level.
More detailed information and the use cases under different requirement will follow soon.
