Gave up on the decal speed Out of ideas for the moment - may try again when my head is clearer.
Actually what I was tring to achieve was a gas cloud a bit like volumetric fog so really little if any movement is needed (a little would be best). Animated fog would do the trick except that it would need to be of irregular shape - complicated in FPSC seeing as it dont seem to have any.
In the meantime I have a work around using a texture applied to a no collison entity with transparency applied for the gas cloud. Looks reasonable and with careful lighting should do the trick - same with water - though I use an animated decal with transparency applied to a collision free entity in the water instance.
Whats needed are true fog and water zones. Workarounds will never cut the ice in professionalism, but we does our best with what we have to work with.
Done lasers (fake of course)...
New doors, teleporters, lifts, conveyor belts, weapons and more to do.
cheers