Does anyone know how to create custom Decals in the SteamVR Hammer Editor? I am trying to create a solid image like a door to "stick" onto the surface of a piece of map geometry.

I understand how to use and create custom Overlays. However, Overlays have an inherent opacity where the player can still see the surface behind the Overlay, so an Overlay doesn't work for this purpose. If I could increase the inherent opacity of an Overlay to 100% (solid), then that would be usable. I'm thinking that what I need is a Decal.

I was able to create custom Overlays using imported VMAT textures pointed to custom TGAs, the "VR Standard" Shader and the Translucent attribute. Then I could place them with the Block Tool / Quad with the custom Material selected as the Active Material. However, for some reason the SteamVR Hammer won't let me use them or anything else as Decals (they don't show up in the Decals area of the Asset Browser, in fact I have no entries here). Maybe there is some additional tag or metadata that I need to attach to the VMAT Material files in the Material Manager to make them work as a Decals?

I've also tried the "infodecal" Entity, and I can't get that to work at all in SteamVR Hammer, regardless of what texture I use or attributes it has.

"Thank you" to anyone who can shed some light on this mystery.

See also this Youtube video, where a mapper is able to use Decals in the HLA Hammer Editor: https://www.youtube.com/watch?v=8xbmiBBFt4s