Is there a way to "virtually" rotate a face normal to get a different shade without actually rotating the face? I was wondering if there's a way to only virtually rotate a face so it gets its light from a different angle, yet the geometry stays the same (like a normal map, but manually face per face) So in essence - rotate a face's normal (which kind of conflicts with the meaning of "normal")

It's a low poly style where I want to have some shading like in a bump map, only it's very low poly and I'd like to design it face per face.

So f.e. - I have a face along an edge where I know its "virtual" angle is slightly more upwards (like bevelling an edge) - but the geometry regarding that face and the ones connected to it did not change.

Especially a problem in a corner where some of those faces would meet and if rotated in geometry intersect and would have to have additional faces that also have additionally different shades due to the geometry.

Cheers and thanks a lot!
What you are looking for are generally called Split-Normals, these are normal values that are stored independent of the geometry they belong to.

Blender has built-in support for them, and even has a modifier that allows basic editing. It can be found in the Properties Window > Modifiers > Modify and is called Normal Edit modifier.

It  provides basic control, but as of version 2.78, as  far as I know it can't be manually controlled as you desired. To best of my knowledge there is no builtin way to manually adjust per-vertex or per-face normals in Blender natively.

There may be third party addons that do allow this though.

One such example is Blend4Web's normal editor. The addon's greater goal is completely different, but if you are willing to install its considerable size it does provide normal editing tools among its functionalities. It can be found under the 3D View > Toolshelf > Blend4Web Tab > Normal Editor.



EDIT Fresh from the news page, it seems that for GSOC 2017 there will be a project tackling normal editing