Since Normals all point to one viewer, negative Z values are not saved (they would be invisible anyway). In Blender we store a full blue area, although some other implementations also map blue colors (128 – 255) to (0.0 – 1.0). Last convention is used e.g. in “Doom 3”.
The steps that are performed when creating and using Bump & Normal Maps are:
- Model a highly detailed (“Hi-Poly”) model.
- Beacon the bump and/or normal map.
- Create a low-poly, less detailed model.
- Assign the map to the low-poly model with a common coordinate system.
The beacon of a model, simply put, is to take the detail of a high polygon mesh and apply it to a similar object. The similar object is identical to the high poly mesh, with the exception of fewer nodes. Use the Render Beacon in Blender function to do this.
Modeling a low-poly with Blender’s mesh editing tools. In general, the same or similar surfaces should be present that reflect the model. For example, a highly detailed ear in the High Poly model may have 1000 faces. In the low-poly model, this can be replaced by a single plane oriented in the same direction as the detailed ear mesh. (Tip: Blender’s multi-resolution mesh modeling function can be used very well here).
Mapping is the process of applying a texture to the Loy-Poly-Mesh. Further information on applying a texture to the material of a mesh can be found in our article on Texture Mapping. Special considerations for Bump and Normal Maps are:
- If you are using a bump map, map the texture to normal and do not activate RGB.
- If you are using a normal map, map the texture to the normal.