HUD can't draw a Material once it contains "material collection parameter", any clue ?


I d like to animate the opacity of a gauge on my HUD, i set-up a blueprint that does that through Material Collection Parameter, unfortunately the material doesn’t draw at all on the screen. it shows though once i remove the Material Collection Parameter. It also works properly on scene geometry.
I tried couple things with no luck : Draw Material, Draw Material Simple, Set Material to Unlit…

Ps: Anything to do with the “set scalar parameter value” being in Level Blueprint instead of HUD Blueprint ?

Thanks for your help

Faced with the same problem. Somehow I think that this is a bug.

I’m not sure if you’ve gotten past this yet, but you’re using the wrong scalar parameter. The one you want has a description of "Sets a mid scalar (float)… not a collection. Unclick the context box to find it when you type scalar

I have the same issues in UE 4.5.1 and in 4.6.1, as soon as I feed a MPC into the opacity of the material that is being used in the hud instead of a constant vector it just disappears, regardless of what the value is ‘meant’ to be…