This is possible. You would need to set up your decal material by adjusting some settings in the details panel.
. (Video here will show you how to set up your material)
A forum post was made asking about materials on glass which can be found here with the answer
When placing the decal using the Deferred Decal from the placement modes your decal material will conform to the meshes that is is being projected onto.
I hope this helps explain what you’re looking to do.
Is it possible to get a decal actor to appear on a translucent material?
For example, blood splatter on glass or foliage on water. I am trying to create that effect at the moment in UE4, but either I am doing something wrong or it doesn’t seem to be possible.
Do you guys have any advice?
This answer contradicts the answer provided in the following thread:
Hey, i try to get a decal projection on a Glass or translucent object. I´ve searched a lot, and found some older posts about this. Seems years ago it didnt work… Is this the same today or is it fixed now and there is any trick or tipp how i can...
I have been unsuccessful in my attempts to get a DBuffer decal to project on a translucent surface and from the answer in the post above, it doesn’t sound like it is supported at the moment. Running 4.13.1
I have not found any official bug issues related to this though.
I’d like to second the mention that this does not get the decal to appear on transparent surfaces. Neither of the links provided a solution to this question.
Has anyone found an answer to this yet?