I thought it was kinda strange, was messing around with craters and this happened. I already posted it in a thread I started, but thought I should put it here as well (sorry if I shouldn't, go ahead and delete this)
I'll definitely take a look at it when I get the chance. Thanks ;).
Nothing weird about it. You just inverted the crater shaders, thus giving you bulges instead of pits :P
I created a thread about that some time ago, check it out:
http://forums.planetside.co.uk/index.php?topic=187.0
yeah, i know. but the second one (on the left) is a different shape than what you usually get when you invert craters
Actually, it's not. The crater shader distorts the underlying terrain. In this case the 1st crater creates a bulge. The second one creates another bulge on the edge of the existing bulge. If you look closely you'll see that' the height is evenly distributed on the bigger one. If you look straight down on it you'll see they're both perfectly round ;)
It may look weird, but it's perfectly logical :) Keep it up, you can really do funky stuff that way.
edit: attached a render so other people can see what this is all about.