I think this is still an issue, which is weird since you have other roofs that don't look like that. Maybe it would be better to modify those to obtain the more "polished" version, than to try to tune down those looking like metal.

Ah right  this might be a tough one to do. Terrain modifications would be op though. The first thing I thought you wanted to do is some kind of model representing the crater. But even this my have a whole bunch of challenge to get along with too...

I’ve only thought about the craters  but haven’t actually done it nor do I know how and as for the aura, I haven’t tried it with anything yet. Craters, I mean actual holes, like those created by the terrain tools in Atlas.

For this the projectile can probably spawn an entity (the crater) with an aura (slow units in the crater), have you tried that? What would cause performance issue?

I used to think about the craters left by explosions since, to me, they serve as a measure of firepower, but it seems they would cause issues for performance and gameplay.