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To add a material, we need to first create a RIS Network.  Note that RIS material is not a SHOP but it is a VOP inside a RIS Network.  A RIS Network is just a container for RIS VOPs.  It is required for Houdini to work with RIS materials. New in RenderMan 22 - a material is represented by a PxrCollect VOP with a BxDF VOP input. To add a material, you can add a PxrSurface from the RenderMan Shelf, which automatically creates a PxrCollect, or select another BxDF from the RenderMan Menu to wire into a collect VOP. These tools also automatically create a RIS Network if it does not exist as well as the selected VOP.

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