Should the normal map be the same size as the texture its based on.Is there adownside to using a smaller normal to save memory size etc?
the only and obvious downside is detail loss. If you reduce the size and don’t notice bad results, it’s probably ok. Normal maps can especially produce weird results if they’re too small. Be careful for image compression too!
Generally your textures should have a size that fits the resolution they appear in your render.
For objects far away, smaller textures are ok.
Ok thx mate I will stick to same size normals.
as above the downside is DETAIL
the advantages of a large NormalMap is you can reduce the size of the Mesh
meshes use WAY!!! more space
i work on asteroids ( real ones )
a uvsphere mesh that is 5760 segments and 2881 rings is 1.2 GIG ( with UV mapping)
a rgb 8 bit /chan normal map that size ( uncompressed ) 47.5 Meg
so for your “Bang for the BUCK” using a small mesh and a big Normal map MAKE A LOT OF SENSE