PBR Textures Metallic vs Specular Workflow
PBR (physically based rendering) is a shading paradigm that has recently gained popularity in the gaming industry. It uses cutting-edge lighting computations. It tries to produce a more realistic lighting environment by properly modelling how light interacts with a surface using lighting physics and actual material values. We now have dynamic light sources that create realistic shadows, as well as image-based lighting that gives correct diffuse and specular reflections in the ambient environment.
There are now two process options for PBR materials: specular and metalness. The purpose for this is so that our users can import these textures into the wide range of 3D apps that are accessible. PBR-Metallic is a simplified version of PBR-Specular. It’s ideal for beginner artists or those that are having problems converting from a specular map to a PBR approach.
PBR Specular Workflow
PBR Specular uses diffuse, specular, and glossiness maps.
- Diffuse map just contains the diffuse colour, no shading or lighting data. Shaders and ambient occlusion are usually baked into the diffuse map when working with styled and/or hand painted textures. Shaders are handled by the system, and ambient occlusion is handled by a separate map in PBR. Metals should seem black on this map because they have no diffuse colour.
- Specular map contains the colour of specular reflections. Non-metals should be grayscale and dull, while metals should be vibrant and colourful.
- The appearance of specular reflections is controlled by glossiness. The strength and size of specular reflections are determined by the roughness or glossiness of a surface, as previously stated. Whiter values indicate a smoother or glossier surface on this greyscale map.
PBR Metallic Workflow
PBR Metallic uses base colour, metallic, and roughness maps.
- Base colour map contains both specular colour for metals and diffuse colour for non-metal. Basically, the diffuse and specular maps from the Specular workflow are combined into this map.
- The metallic map is a greyscale map that tells the shader whether the coloured portion is made of metal or not. Metal is represented by black, while non-metal is represented by white.
- The roughness map is the polar opposite of the glossiness map, with whiter values indicating a rougher surface.
Metallic workflow removes control of the F(0) values for non-metals, which can often be used incorrectly, hence making it somewhat more popular over Specular. It also saves memory because two-thirds of the maps are greyscaled, compared to only one-third in the Spec/Gloss procedure.
Maps common to both Metallic and Specular Workflow
In addition to the above-mentioned maps, there are a variety of other common maps that can be used and are frequently required to produce a desired aesthetic, regardless of the workflow. Some of these are:
– Normal (Roughness/Glossiness map should reflect this added detail)
– Height
– Bump
– Ambient Occlusion
– Opacity
– Emissive
PBR Metalness vs PBR Specular Workflow
Both workflows provide excellent outcomes, but each has its own set of advantages and disadvantages.
PBR Specular Workflow uses a Specular Color map in conjunction with the Gloss Map for correct specularity. This has both a strong benefit and a significant disadvantage, especially in terms of game creation.
| PBR SPECULAR WORKFLOW PROS | PBR SPECULAR WORKFLOW CONS |
|---|---|
| An RGB colour map contains all of the specular features. This map has a really great result because it uses all three colour channels for data. | You lose the option to pack black and white maps into the RGB channels since a full-colour map is used for better accuracy. |
| Diffuse and reflectivity are controlled directly with two clear inputs, which artists with previous shader knowledge might prefer. | Illogical reflectance values are simple to use and produce erroneous results. |
| A complete colour input gives you more control over insulator reflectivity. | When compared to the metalness workflow, it uses more texture memory. |