I’m working with scan data of a cave, pure albedo and isolated specular, so from RealityCapture I brought fbx with cameras, diffuse and normal map (reprojection from 137 M tris to 1 M), then used these assets in Mari to produce a bump map (using paint-through from 85 projectors linked to isolated specular scan data), sweetened normal map (blur tool used to denoise), and then painted a roughness map based on reference photos. Here’s a screen recording from Mari (no audio) faithfully capturing every detail in the rock, in part attributed to the normal map, but the grain-of-sand detail came to life from the bump channel. The isolated specular information feeding bump isn’t ideally suited for what bump is looking for, greyscale (working that issue), but since the normal maps cover much of the fine texture, all I need from bump is the finest high frequency detail to top things off.
Moving into UE5 it’s nice to see shadows and things look basically how I expect, but this screen recording shows a couple reasons for disappointment, normals not nearly so clean as I left them in Mari, and bump offset node does not deliver that grain-of-sand-detail I see in Mari. I was sure to deselect sRGB for roughness, normal, and bump maps, show my material setup, am hoping somebody really savvy with data channels can help me pinpoint how these maps that perform so well in Mari get lost in translation in UE. Okay, lost is overboard, but appreciably diminished. This work isn’t merely about satisfying for believability, I’m needing to preserve a value around “empirical”. Many thanks for your time.