Surface Normal Node
The Surface Normal node creates an image that can be used as a bumpmap, a displacement map, etc., to control the perturbation of an image in another node, such as the Vector Warp node.
The Surface Normal node uses a single, user-selectable channel of the input image. A vector perpendicular to the surface is calculated for each pixel of the selected channel by taking a weighted average of a sample of surrounding pixels.
The data is output as a two-channel floating point image, with the value for the X component of the normal in the red channel, and the value for the Y component in the green.
- Note:
- The Surface Normal node is similar to the Bump node, but Surface Normal offers more control over the output by enabling you to specify the number of surrounding pixels to sample and the radius of the sample area (refer to the parameter descriptions below).
Surface Normal Parameter Tab
Sample Radius
Pixels are sampled along the circumference of a circle surrounding the pixel currently being processed. The Sample Radius parameter enables you to set the size of the radius that defines this circle. The radius size is expressed as a percentage of the total image size.
You may wish to increase or decrease the radius of the sample area depending on the level of detail in the source image and the effect you wish to achieve. For example, a larger radius would result in a loss of local detail when used for an image with many fine lines. You can key a value into the data entry field or use the mouse to set the tuner to the desired value.
Samples
The Samples parameter enables you to specify the number of surrounding pixels to be sampled. The minimum is 4. Larger sample values take longer to process but produce a more accurate result. You can key a value into the data entry field or use the mouse to set the tuner to the desired value.
Channel to Use
This parameter enables you to specify which channel of the input image should be used to calculate the surface normal for each pixel by selecting the desired channel from the Channel to Use popup menu.
Table of Contents | Index
Copyright 1996-1999 by Silicon Grail Corporation |