It would be nice to be able to associate an instance of a material parameter collection with a material instance. Many products use MPC’s for controlling various aspects in the material such as wind speed and direction. For example, with Megascan Trees the material is setup with an MPC to control wind speed and direction. The problem is that this is global. So, if I want to have various biomes where in one area trees move at a different speed than another area this cannot be accomplished with the MPC as MPC’s are global. This is even more relevant now that we have the new PCG Biome plugin for UE 5.4. Currently it could be possible to use Custom Data in Materials Per-Primitive but this would require a reworking of any existing materials that currently use an MPC. It would be so much easier to just specify a MPC Instance for each Material Instance and then change those parameters in your blueprints by choosing a particular MPC instance.