It seems like a big issue, I have a repro below, or is there something I'm forgetting? Thanks.
- Create new material "TestMat"
- Add scalar parameter "TestParam = 26"
- Place Shapes > Sphere in the world
- Assign TestMat to the sphere
- With the sphere selected place PolyReduce HDA from Houdini Tools shelf
- Change "Percent To Keep" to see it's working
- Change "Houdini Inputs > Input Geometry > Export Material Parameters > On"
- Recook
- Open Scene in Houdini
- Open he_polyreduce, select input node
- Observe unreal_material_parameter_TestParam is missing in H20.5 but is present in H20
P.S. Is there a better way of passing data from Unreal to Houdini, say per spline?