Attrib Composite surface node

Composites vertex, point, primitive, and/or detail attributes between two or more selections.

See also: Attribute, Attrib Create, Point, Primitive 2 more , Vertex, Blend Shapes

The attributes may be explicitly specified in the corresponding attribute text field. Exclusion is specified by preceding an attribute name with the carat character (^). All available attributes can be specified by leaving the field blank or entering an asterisk (*) in the field. If the first attribute is preceded by a carat then all attributes are assumed to be transferred except where explicitly excluded. In all other cases, no attributes are assumed except where explicitly included.

The specified attributes of the ordered inputs are composited in sequence. The attributes are first scaled by the corresponding blending weights and then composited using the specified compositing operator. The available operators include Mean, Max, Min, Over, and Under. The Mean operator determines the weighted average of the input attributes. The Max and Min operators determine the maximum and the minimum of the weighted input attributes respectively. For the Mean, Max, and Min operators, the specified Alpha Attribute affords a per-point, per-primitive, or per-vertex weight distribution. The Over and Under operators perform two of the standard alpha blending operations where the alpha values are taken from the specified Alpha Attribute. The Over operator scales the incoming weighted input attribute by its alpha value and adds it to the current intermediate output attribute scaled by one minus that alpha value:

source * alpha + destination * (1 - alpha)

The Under operator is performed in a similar manner but with the alpha weights swapped:

source * (1 - alpha) + destination * alpha

If the Alpha Attribute does not exist for a particular input, then the alpha mask for that input is assumed to be 1.