I am interested in normal edit mode and think its a MUST for any software used for output to OpanGL/DirectX rendering engines since they all accept pre-calculated normals.
For the feature- you could even hack vert paint mode to impliment normal edit mode- paint vertex normals like you were saying in Maya.
- Just display normal direction rather then colour???
The normal data would be stored per face, but each point on the face having a seperate normal.
Almost exactly like vertex colours - Just a XYZ for each point in each face rather then an rgb.
I thingk the normal editing would be very similat to vertex painting in the way it fits into blender.
face select >>
Of course normal edit could be done in object mode too, youd just be eding all the normals at once, for every face (just like vert and texture paintpaint)
You would need some functions (Special menu Im thinking)
-Recalculate Smooth (shared normals)
-Invert (Very different to flipping normals in edit mode since this only affects light refraction)
These would be used in most cases, but you need manual editing of normals too (3-4 per face)
I am thinking ance you were in normal edit mode there would be 3-4 edges more face poking out of each face (Visually) Inset a little so you can see whitch normal belong to each face. and you could select them and modify them a little like verts (boarder, paint etc), Proportional editing (Okey) woul be very cool too.
Most used would be the rotate tool.
Not sure if grab would even apply.
The other thing is you would need to see what the normals looked like as you were editing them- Have OpenGL light refreacions easely toggeled on and off so you can see what it looks like.
BTW- This would be very cool with raytracing, you could get some hand edited refractions since refractions use the normal data.