# Known issues and limitations

There are always cases where things does not work quite as expected, issues or limitations caused by various reasons. We'll try to list common known issues and limitations below to make users aware of the issue and possible workarounds.

# Simplygon and Bump-maps

There are cases of where materials utilize bump maps (grayscale textures) for detail preservation. It is not uncommon that these textures get sent through Simplygon's NormalCaster as if they were normal maps. The baked normal map will in this case not be correct, neither as a normal map or bump map.

The reason for this is that Simplygon simply does not support bump maps. A NormalCaster always expects a normal map where each pixel (in use) is a valid normal, this is not the case for bump maps. When a bump map is sent to a NormalCaster each pixel will be treated as a normal, and incorrectly get transfer to a normal map (incl. correction of the reduced surface).

Bump maps can be baked using a ColorCaster, but with the limitation that the baked texture will not include compensation of reduced geometry (less accurate).