Yeah. I know I lost the glow. It only really shows up where the rock is in shadow but then I get the exposure problems in the shade. I'm thinking of setting up a planet where I have control of all the surface lightness as a kind of exposure hack.
Volker. I used elements of smoothing just about everywhere so yes if I understand what you mean then smoothing was used as you describe.
The terrain that the rocks are on is actually simply a perlin billows powerfractal. There is another perlin fractal for terrain which supplies some lower undulations but I've found that you can tweak all the parameters of the power fractal to get kind of spires but not lots of nasty sharp spikes because you can use the spike control and also the smooth control in compute terrain. You don't really want spikes but more smooth bulges. Ironically I did use the other spire technique for some very small rocks which you can faintly see in the first render. Discussed here:
http://forums.planetside.co.uk/index.php?topic=2530.0Except in files on that thread a colour adjust shader was used to get something to mask with. I replaced this with a conditional scalar.
The reason for using this technique was more to do with the fact that I needed to clamp and mask what looks like small stones so they had different materials (can't really be seen clearly in these first two renders). Fake stones are cool but they are voronoi and always look so. Clamping and masking perlin gives you some other options.
The ideal set up (or really compromise) for this kind of extreme displacement is to set up terrain that is peaky and steep as possible while keeping it smooth with low detail then the smaller overlying displacement provide that detail without having lots of underlying terrain detail clashing with it. Smoothing in the surface layers is also effective. This is one of the great things about TG2's displacements. There are lots of various ways to smooth them out. Other apps tend to get masses of artifacts with nasty clashing angles.
You also find a problem at the hill peaks. This is where big displacements tend to get seriously messed up. The altitude drive I use blows the terrain up like a balloon and so smoothes out this top area = smoother overlying displacements.
