Normal Map

[brucelay]

Hi there,

Which part of normal map is better than traditional bump map.

Normal map has been so popular in these few years. no mater people are from the game industry or movie orZbrush modeller. But why people nowadays prefer using normal map to bump map? Which one can produce better quality? Why?

some website explained a lot about tangent space or something...... but why is it better than bump map?

thanks for your attention!

[sibarrick]

well put simply (i hope )

a bump map only stores the "faked" height of the bump along the surface normal.

a normal map stores what direction the normal is pointing in after the bump.

therefore the surface shading will be more accurate in the second case because the normals are going to be correct for the bumpy surface.

Its worth noting though when you do a bump map in vops you can use the displace along normal vop which does a true displacement and then calculates the normal from the displaced/bumpy surface (the final surface isn't actaully displaced because you are doing it in a surface shader not a displacement one) therefore I've always assumed the result will be just as good as a normal map. Maybe not as quick though... not sure

There are other ways to calculate the normal after a bump map but they are never as good as really doing the displacement, I think this is where the talk about the differences between the two approaches stems from.