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Vstructs or Virtual Structs are a way to connect a set of parameters from one bxdf/pattern plugin or OSL shader to another set, while representing this connection as one virtual struct. Simply put, the artist connects a vstruct in a shader network and behind the scenes, many connections of existing parameters are made. For example:
PxrSurface as an example
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To take this idea a bit further we can also make connections only if a criteria is met. Let's say for example there is a parameter called "enableDiffuse" on our Layer pattern in the above example:
Vstructs Conditionals
We only want to make the diffuseColor connection if enable diffuse is turned on of course. So using a second piece of metadata "vstructConditionalExpr", we can define when to make that connection.
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