Heya Fabrice,
Have you tried running the game either in Simulate in Editor or Play in Editor? In the latest build here, it works as you’d assume but only while playing the game:
In this case I just plugged your setup into Base Color to make sure I don’t get any crazy blooming effects. But while in editor it’s crazy blown out, looks like the error material used for checking if poly’s are outside the Actor bounds.
I’m going to file a bug report for how it’s behaving in the editor. But, if it isn’t working for you in game or simulate, I can tell you it has been fixed in the latest internal build.
Cheers!
Ian