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This node removes material bindings from geometry primitives. You use this LOP when you don’t want a USD primitive to be affected by any material.
Because USD allows a few ways to bind a material, and because direct material binding on a parent affects its children, this LOP may need do more work than merely block a direct binding on the specified primitives. For example, it may need to block material binding relationships on ancestors primitives. And to preserve the look of unaffected siblings, it may need to transfer the binding from ancestor to these siblings. In addition, it will need to remove the specified primitives from any collections used for collection-based material binding on ancestors.
Tips and notes
You can unassign material from many primitives either by specifying a pattern in the Primitives parameter, or by increasing the Number of Primitives.
You can easily enable and disable the removal of a material, by toggling the __Enable_ checkbox on or off.
To block a single direct or collection-based material binding on some primitive, without affecting parents or siblings in any way, you can use Edit Properties node, and import the binding relationship for editing, and then set the action control parameter to “Block”.
To explicitly remove a primitive from a collection-based binding, you can use Collection node, then set the Primitives parameter to
%self, turn on Add Exclusions, and set Exclude Primitives to your primitive (e.g.,
Or, alternatively, just set the Primitives parameter to
%self - /path/to/my/prim.
Number of Primitives
Specifies number of available material un-assignment rules. Usually there is one rule per primitive (or set of related primitives).
Toggles the removal of the material binding on and off.
The primitive(s) from which you want to unassign the material. You can click the select button beside the text box to select the primitives from the scene graph tree. You can also use primitive patterns for advanced matching.
Specifies which materials to unbind.
In USD it is possible that a geometry primitive may be bound to several materials, either through various mechanisms (eg, direct or collection bindings), or at different ancestor levels. Only one material wins in the end, but unbinding that single material means that the next material in the precedence order becomes the active one.
All potential materials are unbound, leaving the geometry primitive with no binding at all.
Unassign N (Debug)
The USD binding purpose for which to unbind the material.
Number of Materials
When unbinding only a limited number of bound materials, i.e., when Unassign All Materials toggle parameter is off, this parameter specifies how many top priority materials should be unbound.
This parameter is useful for debugging the USD scene to investigate the order of material bindings.
A comprehensive set of simple examples for the Unassign Material LOP.
This example demonstrates simple cases of un-assigning material and the effects on the cooked USD stage. Eg, it unbinds a material from one of the several sphere primitives, and shows that the material no longer has effect on that single primitive.
In addition, this exmaple file explains various parameter configurations and their impact on the Unassign Material LOP.