Post #6by selden » 24.05.2008, 11:56
Unfortunately, English is ambiguous and is causing you both to misunderstand one another.
In common English, "normal" means "ordinary". A normal map is a image of the terrain. It might show the coloration of the ground, roadways, political boundaries, or other information about a region.
In Celestia, this is a Texture.
In 3D graphics, however, and in Celestia, it means something quite different: a "normal map" is a file which contains values of surface normal vectors.
In Celestia, this is a NormalMap.
If you use a NormalMap, you should not use a BumpMap.
A "surface normal vector" is the direction which is perpendicular to the surface of an object. As a result, a "normal map" describes the irregularities in the surface of a 3D model. It is used to help calculate shadows, making a flat surface appear to have protrusions. Normal maps are usually converted into image files for use with 3D graphics software. When viewed with an image viewer, they seem to have various shades of pink and blue, depending on the tilt of the surface at each pixel location.
In 3D graphics, a "bumpmap" contains values which are proportional to the height of a location. Celestia internally converts bump maps into normal maps. Bump maps are usually converted into image files for use with 3D graphics software. When viewed with an image viewer, bump maps seem to have various shades of grey. Their pixels are white at the highest altitude and black at the lowest.
In Celestia, this is a BumpMap.
If you use a BumpMap, you should not use a NormalMap.
Selden
I forget.
