Is this Normal map correct

Question

I want to know whether this normal map i created is correct.. I was expecting where the object is planar, it should have pure blue color, no component of red or green color... But clearly this is not pure blue. I created this using 3DS autodesk 2011

Answer 1

Yes it looks ok. Since the components of the normal is in the range [-1, 1] they need to be remapped to [0, 255] before they can be stored in the normal map. This is done by:

remapped = (value * 0.5 + 0.5) * 255

For a normal of [0 1 0] you get a value of [128 255 128].