Bump Icon

asBump

A node that allows the user to apply scalar bump mapping, or normal mapping.


Parameters


Mode Parameters

Mode

The choice of bump mapping algorithm to use. It can be one of:

Bump Parameters

Bump Value
A scalar value controlling the magnitude of the bump effect.
Bump Depth
A scalar value controlling the bump depth of the bump effect. Unlike the bump value which expects a value in [0,1] range, the bump depth can be a positive or negative value, in which case it will apply the bump effect outwards or inwards respectively.

Normal Map

Normal Map Weight
A scaling factor that defines the contribution weight of the normal map. With a value of 0.0, no contribution takes place and the regular surface normal is used. A value of 1.0 defines full contribution of the normal map input.
Normal Map
The input normal map color.
Map Coordinate System

The coordinate system of the input normal map used [1]. It can be one of:

  • Tangent Space
  • Object Space
  • World Space

Advanced Parameters

Map Signedness
The signedness of the input normal map. If your map is in [-1,1] range, use Signed. If your map is in [0,1] range, used Unsigned.
Flip R
Flip the red channel of the input tangent space normal map.
Flip G
Flip the green channel of the input tangent space normal map.
Swap RG
Swap the red and green channels of the input tangent space normal map.

Note

The channel flipping and swapping options only have effect on the tangent space normal maps. They are ignored when the Map Coordinate System is Object Space or World Space.

Surface Parameters

Surface Normal
The base surface normal to use. It can be the result of a previous bump node, or the global variable N from the asAttributes node. If not set, it defaults to the (world space) surface normal N.

Outputs

Result
The unit length world space bumped normal.

Footnotes

[1]Usually one uses tangent space normal maps, but the option is provided here to use object and world space normal maps, which sometimes can be exported from other applications.

References

[Bli78]James F. Blinn. Simulation of wrinkled surfaces. SIGGRAPH Comput. Graph., 12(3):286–292, August 1978. URL: http://doi.acm.org/10.1145/965139.507101, doi:10.1145/965139.507101.
[CMSR98]P. Cignoni, C. Montani, R. Scopigno, and C. Rocchini. A general method for preserving attribute values on simplified meshes. In Proceedings of the Conference on Visualization ‘98, VIS ‘98, 59–66. Los Alamitos, CA, USA, 1998. IEEE Computer Society Press. URL: http://dl.acm.org/citation.cfm?id=288216.288224.
[COM98]Jonathan Cohen, Marc Olano, and Dinesh Manocha. Appearance-preserving simplification. In Proceedings of the 25th Annual Conference on Computer Graphics and Interactive Techniques, SIGGRAPH ‘98, 115–122. New York, NY, USA, 1998. ACM. URL: http://doi.acm.org/10.1145/280814.280832, doi:10.1145/280814.280832.