Hydra surface shaders with shader parameters whose values are set to the defaults are not applied correctly in the drawing of facesets on polymesh locations.
Steps to reproduce:
Create a PrimitiveCreate node and set its type parameter to cube.
Create a FaceSetCreate node downstream, set its meshLocation parameter to the same location as the PrimitiveCreate node (e.g. /root/world/geo/primitive), and set its selection parameter to 0-2.
Create a Material node downstream, add a shader of type hydra > surface to it, and set the hydraSurfaceShader to katana_constant.
Create a MaterialAssign node downstream, set its CEL parameter to the location of the faceset, e.g. /root/world/geo/primitive/faceset, and set its materialAssign parameter to path of the material location created by the Material node, e.g. /root/materials/Material.
Set the view flag on the MaterialAssign node, expand the entire scene graph, and inspect the drawing of the cube in a Viewer (Hydra) tab.
Expected behaviour:
Three faces of the cube should be drawn in red.
Actual behaviour:
None of the faces of the cube are drawn in red.
Workaround:
Toggle the state bade of the katanaColor parameter of the hydraSurfaceShader on the Material node, so that the red color is set as a local parameter value, rather than a default parameter value.