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)
– Ambient Occlusion
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 Metallic workflows are memory friendly in nature and hence often more suitable for game development.
|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.|
|PBR Metallic Workflow Pros||PBR Metallic Workflow Cons|
|Metallic can be used in a colour channel in a ‘packed map’ because it is black and white. Different grayscale textures are included in each possible colour channel (Red, Green, Blue) in these maps. MRA maps (Metallic, Roughness, Ambient Occlusion) or something similar is a frequent approach to save memory when utilising PBR-Metallic.||Artefacts can develop because Metallic Maps provide less information than a Specular Color map and are used as a mask in the shader. It’s usually small, but it can be a major issue on occasion, especially in games with intricate surfaces directly where the player camera is.|
|The albedo map defines the colour of an item regardless of the type of substance, making it theoretically easier for artists to grasp.||White line artefacts are caused by material transition points.|
|Materials are simplified into two categories, insulators and metals, which may make creating content with unrealistic texture values more difficult.||It gives less control over reflectivity for insulators|
|When compared to a full-colour specular technique, it uses less texture memory.||It’s possible to use incorrect values in the metalness map and disrupt the system if artists don’t grasp workflow.|