Adeptus Sororitas wrote:
2. I want the casing and shells stay on the ground; means: never vanish. They should not be 'acid shells', stay on the ground and stay there ... I don't want "But it's better for the performance ..." - I want to see a destroyed and hard fought battlefield.
You'd have to increase the material integrity of the shell, like to Dirt or Stone. I think there are only a few shell types, but if you don't want to do it I can take a swing at it. Shouldn't be too hard. They would still vanish if you dug them, like any terrain, but they would at least stay there when you walked on them.