Bump Node
The Bump node enables you to create a bumpmap that you can use for embossing or other rendering effects. A bumpmap is a pseudo-3D image that contains a surface normal (a vector perpendicular to the surface) for each pixel of a selected image channel. During the Bump computations, the surface normal of each pixel is encoded as two floating point channels:
- a float value for the X component of the normal in the red channel
- a float value for the Y component of the normal in the green channel
The value of the normal is based on the rate of change between the current pixel and neighboring pixels of the selected plane.
The Bump node accepts one input, which can have from one to 10 channels. For each pixel the Bump node examines the values of adjacent pixels on a single selected image plane (channel) and creates the bumpmap. You can apply the bumpmap perturbation
- over another image using the Emboss node to create an embossed effect,
- over the source image using the Emboss node to give the image an appearance of greater dimensionality, or
- over another image using the Vector Warp node to create a displacement effect such as a ripple or other distortion.
Bump Parameter Tab
Bump Scale
The Bump Scale parameter enables you to specify the degree of relief of the bumpmap by keying in a numerical value or by using the mouse to set the tuner to the desired value. The higher the value, the greater the effect.
Channel to Use
The Channel to Use parameter enables you to specify which channel of the source image the Bump node will use to calculate the surface normal for each pixel. You set this parameter by selecting a channel from the popup menu.
Smooth
Check the Smooth parameter box to soften the bumpmap's edge transitions to create a softer slope or more "rounded" effect when compositing. The Bump node creates the smoothing by taking an average of the pixels surrounding the current pixel on the left and below it before calculating the bump for the current pixel.
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