What are PBR Textures?
PBR, or Physically Based Rendering, is a model of shading used in computer graphics that more closely mimics the flow of light in the real world.
PBR textures produce a higher quality of realness with greater variations of lighting, producing flexibility and predictability in the final product.
PBR texturing’s most popular workflows are specular, and metalness workflows.
Supported by many 3d applications and game engines worldwide each has its unique appeal to the individual user.
To create material in specular workflow you will need the following maps:
- Albedo (Diffuse) Map – base color input, which is the most important map, giving information about the color of the object.
- Specular Map – defines an object’s shininess by using a greyscale map. In its practical application the brighter the shade, the more light will be reflected.
- Glossiness Map – this map controls the reflectivity of an object, whether the reflection of light will be blurred or sharp.
- Normal Map – this map determines the number of dents and bumps an object has. Similar to a bump map yet more advanced, the normal map is saved in RGB format, containing its information in XYZ axes.
- Height (Displacement) Map – this map is saved as a grayscale which creates a larger group of convexities and creases which affect the objects mesh.
The Metalness workflow utilizes the following maps:
- Albedo (Diffuse) Map – this map works the same way as the Specular Workflow.
- Metalness Map – saved as a grayscale this map controls the amount of reflectivity of a surface. The white translates into a pure metal surface, while the black translates to non-metallic surfaces.
- Roughness Map – this map works similarly to the glossiness in the specular workflow. It is also in grayscale and stores the same information yet is inverted. This means that the black color in this map will have a sharp shiny finish, while the white has a fuzzy (matte) finish.
- Normal Map – this map creates bumps and dents as in the specular workflow.
- Height (Displacement) Map – this map is used in the same way as the specular workflow.
In both of these workflows, you may not need all the maps in all situations, such as the normal map or the heightmap. At other times you may only need specific maps, such as the Ambient Occlusion map or the Emissive map. Each texture has its own needs.
Using PBR Textures
When planning to use textures created for the specular workflow in Unreal Engine, you need to convert the glossiness map to the roughness map. To do this, use the OneMinus node to connect between the texture map and the roughness map, which will invert the image. This means black will be white and white will be black.
In addition, connect all the other textures as usual. The Diffuse map for the Base Color, and the Reflection for Specular and the Normal for Normal.
When creating PBR material in Unity 3D using specular workflow, you must change the shader of the created material to Standard (Specular setup). There is no separate slot for Glossiness, and you will need to use the Alpha channels in either Albedo or Specular maps. Paste the Glossiness map into the alpha channel of the specular map in any 2D editing application.
Finally, add the map to the Specular slot, the diffuse map to the Albedo slot, and the normal to Normal, and height to Height.
3ds max and V-Ray
If you’re using 3ds Max with V-Ray, use the material editor to create a regular VRayMtl. Then add the diffuse, reflection, and glossiness. In the bump slot, add the VRayNormal map. Inside it on Bump Map load the Normal map. You can also add a VRayDisplacementMod modifier to the object with the Height map as a Texmap.
With Substance Painter you can also use PBR Textures to create your own personal textures, inserting all the maps into their appropriate slots and loading it as a stencil or fill layer. Remember to set either specular or metalness before you begin.
The use of PBR textures provides more coherent, realistic and predictable results. It also works well under different lighting conditions, and thanks to Normal and Height maps you will get a satisfactory effect without the need to model extra details. Therefore, regardless of whether your work is related to the game industry or architecture, it is worth knowing what benefits Physical Based Rendering gives you.