A reliable workflow
RNM blends directions, not colors
RNM rotates the detail normal into the base normal's frame instead of averaging their encoded RGB colors.
Test both neutral-map identities
A neutral detail input preserves the base, and a neutral base preserves the detail—two useful identity tests for a combiner.
Control tiled detail before mipmapping
Tiled microdetail should be scaled and masked deliberately; excessive high-frequency strength can shimmer once mipmaps are generated.
Give the base and detail maps distinct jobs
A normal map combiner works best when the base map carries broad form and the detail map carries smaller repeatable structure. Set the input Y convention for each file before blending, because two individually valid normal maps can disagree about tangent Y. Match or deliberately tile the detail map, adjust its strength at the final material scale, and use a mask when microdetail belongs only on part of the surface. This preparation prevents the normal map combiner from smearing large shapes or applying pores, grain, or scratches to implausible regions.
Test the blend with neutral normals
RNM reorients detail around the base direction and is generally more faithful than averaging encoded colors. Test the normal map combiner with a neutral detail map: the base should remain unchanged. Then use a neutral base: the detail should remain. Inspect the composite for clipped channels, harsh grazing vectors, seams at masks, and shimmer after downsampling. Simple and UDN modes can be useful for compatibility comparisons, but choose by rendered evidence. Export a normalized lossless result and record input conventions, tiling, mask, and strengths alongside the normal map combiner output.