The Megascans Plugin for Unity supports channel packing and will automatically channel pack the texture as per your render pipeline (Standard, HDRP and LWRP) and your PBR workflow (Specular and Metallic).
Plugin channel packing - Unity Standard Shader (Legacy Pipeline)
Unity's standard shader extracts the Height (Displacement) information from the G channel. Since the G and B channels of the Masks map are free, we pack the Height and AO textures in them so that if you are using a custom shader you don't have to sample a lot textures or channel pack textures manually.
Currently the order is incorrect i.e. Displacement should be in G while AO should be in B channel. We will fix this soon though this shouldn't break your workflow since we are importing the Displacement and AO maps separately as well.
Here's a breakdown of what textures (as referenced by the ones obtained by direct download) are assigned to each channel:
- Albedo (RGB), Opacity (A)
- Normal (RGB) - Our Normals coincides with OpenGL (Y+)
- Displacement (RGB)
- Occlusion (RGB)
- Translucency (RGB)
- If using Specular Workflow: Specular (RGB), Gloss (A)
- If using Metallic Worflow: Masks: Metalness (R), AO (G), Displacement (B), Gloss (A)
Supported Image Formats
Currently, the plugin only supports JPG and PNG because the channel packer in it cannot handle other image formats like EXR, TGA and TIFF.