Are your normals/etc… packed into parallel atlas pages (e.g., each map of a given sprite has same rect in each atlas, so base is at X1Y1…X2Y2 in atlas 1 and normal is at X1Y1…X2Y2 in atlas 2)? If so, then you can get away with creating a single material per atlas page in order to do normal maps / masks / etc… I wouldn’t create sprite assets for additional images (normal, mask, etc…), just create sprites from base color set, and reference additional textures in your material.
Support for multiple textures on a sprite is planned, hopefully for 4.8, however it will still have limitation of each map needing to be in same relative location (only sending down one set of UVs per sprite vertex). I hadn’t given much thought to import from spritesheet workflow in that case though, good food for thought.
Cheers,
Yes in general I create one atlas map for each part of material, i.e Base color, Normal etc actual sprites and in same location on each atlas. I have no idea how to do what you suggested at moment but I’ll get to it at some point, still only my second day with UE4.
Thanks again for your help.