Hi, we use Material Parameters to pass data from Unreal into Houdini and this stopped working when upgrading from Unreal 5.3.2 + Houdini 20.0.688 to Unreal 5.4.4 + Houdini 20.5.370.

It seems like a big issue, I have a repro below, or is there something I'm forgetting? Thanks.

  1. Create new material "TestMat"
  2. Add scalar parameter "TestParam = 26"
  3. Place Shapes > Sphere in the world
  4. Assign TestMat to the sphere
  5. With the sphere selected place PolyReduce HDA from Houdini Tools shelf
  6. Change "Percent To Keep" to see it's working
  7. Change "Houdini Inputs > Input Geometry > Export Material Parameters > On"
  8. Recook
  9. Open Scene in Houdini
  10. Open he_polyreduce, select input node
  11. 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?