About
Cities Skylines 2 uses a modified version of the standard Physically Based Rendering (PBR) workflow, utilizing the metallic/glossiness approach, with a few additions to cover the game's needs.
Texture sets
Textures must be named after their corresponding mesh, with the texture type as a suffix. For instance:
For a mesh named "MyBuilding.fbx", the textures must be named as follows:
- MyBuilding_BaseColor.png
- MyBuilding_ControlMask.png
- MyBuilding_MaskMap.png
- MyBuilding_Normal.png
- MyBuilding_Emissive.png
Important: suffixes are case-sensitive
Channel structure
BaseColor
RGB channels (Diffuse Map) - the diffuse map for your mesh
Alpha channel (Opacity) - Determines the transparency of the texture. Values above 50% gray will be opaque and values below 50% will be transparent.
ControlMask
R channel (Color Mask 1)
G channel (Color Mask 2)
B channel (Color Mask 3)
Color masks come in sets of 3 and are used together. Each color mask should be mapped mutually exclusive to other color masks (don't overlap them on the texture). Black through to White applies the selected colors to the diffuse map using multiply blending. Black is no color, and White is full color.
This greatly increases the variations that you can add to your buildings.
Alpha channel (Snow Remove) - Indicates areas on the mesh where snow won't appear. White is no snow, Black is full snow.
MaskMap
R channel (Metallic) - Defines how metallic the diffuse renders in the game. White is full metallic, Black is not metallic at all.
G channel (Coat) - Adds a glossy layer on top of the standard glossiness, with white indicating a full coat and black none.
B channel (Default Black) - This channel is not currently used and should remain Black.
Alpha channel (Glossiness) - Defines the glossiness of the diffuse. White is very glossy, Black is not glossy at all. In the standard PBR workflow, glossiness is the inverse of roughness.
Normal
RGB channels (Normal Map) - Uses OpenGL format to add depth and detail to the diffuse textures, simulating 3D characteristics on a flat surface
Emissive
Greyscale channel (Emissive Map) - Applies an emissive effect to diffuse, White is full bright emissive and Black is no emissive.
Resolution
All imported textures must be the same resolution.
Textures must be square - 1:1 ratio. Non-square textures such as 1024x512 2048x512 4096x1024, 256x1024 etc, will result in problems in rendering.
The game uses virtual texturing which will automatically downsize texture resolution based on the user's settings. For buildings, the resolution should be 4096x4096 pixels. Smaller buildings like storefronts can have 2048x2048.
Format
Use a lossless format like .PNG.
Make sure the texture is 8 bits/channel.