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HUD won't update material with Material Collection Parameter values.

Hello Everyone, I’m having some troubles with drawing a material in the HUD, which is essentially acting as a form of crosshair, The material has it’s opacity controlled by a material collection parameter scalar parameter, which is in turn controlled by the player character that when a button is pressed the opacity will be set to 0.5 and when that button is released it will be set to 0. Now the actual setting part of the MCP is quite simple and easy, and it ‘should’ work but for some presently unknown reason as soon as the MCP controls the materials opacity, it will not be drawn on the HUD regardless of what value the MCP has, once I remove the MCP and just use a standard scalar parameter the material shows up correctly on the HUD.

I have attempted this in both 4.5.1, and 4.6.1 and the results are the same, I read in the documentation that using an MCP would basically make the material need to be rebuilt in the shaders when the value changes, or something close to those lines, would that be the reason for this not working?

I had same problems, but in my case it was always opaque white or black. Use instanced materials, or do not use UMG for hud.
Currently i am using some meshes in worldspace attached to camera, luckily my game is simple with minimal hud.

I tried using an instanced material and the result was the same, I haven’t even touched UMG yet so it isn’t that. I tried the mesh in front of the camera trick but it has this nasty blurring when moving fast…

Instead of making a new post I thought I would just bump this one, I am still trying to figure this out.

For that blurring turn off motion blurr in postprocess volume, it looks just ugly in most cases anyway, in those it looks fie you do not notice it.

4.6 improved many things in UMG, for eg there is finally way to map mouse (hopefully touch events) to widgets just in gui without any extensive trace or calculations. Still i see no logic in many concepts there ( eg. why border has 4 mouse events exposed while button has only click), but umg is getting there.

Also carefully check what is visible on screen in different resolutions, this is major pita without umg.

Would I be able to use a material with using a material collection parameter to set the opacity of the material on the fly in UMG?

I don’t see why this wouldn’t work, can you post a screenshot of your setup?

This will not work in 4.7 preview 1 as MPC’s are not working currently (this will likely be fixed in preview 2), but any version before that should be just fine, I use them all the time.