I see. Well I succeeded to avoid that and play it perpendicular to the surface, but yeah for some reason it appears weirdly rotated. I also rotated the origin (commented function) to see if the fx follows the forward vector of the origin, but apparently it does not, which is the root of the problem :confused:
Give it a try and do this lil workaround, normally it should be OK for axis-aligned surfaces. If it's no use then you'll have to go with the model approach.
PS: In FX editor make your fx spawn 1 unit ahead in forward vector, so that it doesnt coincide with the surface and do that "flashing" thing. I left you an .efx I used inside the .iwd which has that already.
Attachment 1664