rock formations anyone?

[rcallicotte]

I've messed with this a little today, but found that moving the camera will blow up TG2.  I've stopped experimenting for now.

[Virex]

Hmmm? Last time i tried that, nothing weird happend. Need to check again on this scene though.

Edit: Moved the camera: Nothing exploded.

I've added another test render. Twitching up the patch size worked a bit, maybe. But the biggest change was made by altering the displacement levels.

[Virex]

I think I might have found a break-even point now. Increased the compute normal patch size further by a factor 2, altered the visible terain a bit and increased the invisible terain displacement a lot to compensate.

Edit 1: Seems like i've found out something about the compute terain node: increasing the patch size will get those stripe effects. Seems like we'll have to work everything through the compute normal node.
This got me interested as to what the effect of a realy low compute terain patch size would do. Increase the resolution of a terain perhaps?
Subedit 1: Rendering with a lower patch size won't affect the cracks, but it'll get rid of the bands.

Edit 2: I think that to get the best effects, the compute normal patch size must be close to the visible terains feature scale. I don't have time to test that yet though.

Edit 3: here's the render and the TGD.

[peejay]

calico - I haven't had any problems with the camera other than finding myself inside a massive displacement.

virex - cool experiments  - yes patch size seems to help a lot. But rather than pushing up the displacement value, I've found better results by using a really low displacement value in the hidden terrain and pushing up the buoyancy from variation, and clumping of variation values. I still can't get anything to complete a render in this program over 1200 by 1000 though, no matter what kind of landscape it is. Here's hoping the full release version will solve that.
Your results look promising, given that there's a whole planet of it, might be worth exploring to see what interesting forms are lurking a few thousand kilometers away?

[rcallicotte]

The problem I had was related to another set of functions I introduced.  Extreme displacements usually blows TG2 out.

I'll try it again later.  I'm experimenting with other things now. 

calico - I haven't had any problems with the camera other than finding myself inside a massive displacement.

[Volker Harun]

This looks promising ... I have absolutely no time ... but ,-)

[Volker Harun]

From experience, keep the patch size high.
Play with the diplacements' spike limit which is like the contrast. bouyancy and clumping are ways for fine tuning.

That last tgd is a fine one to play with those values.

Your first idea of the crater shader could be solved more easily and faster without that 'compute normal' which is very time consumpting.

Another way of creating such effects can be found here: http://forums.planetside.co.uk/index.php?topic=1960.msg19196#msg19196

The useful node is the merge shader ,-)

Volker

[peejay]

thanks Volker

I'm in the middle of a 3-4 day render so I'll play a bit more when it finishes (or crashes)

[peejay]

The attached show a proof of concept Hoodoo using cylindrical displacement mapping on an inverted crater.

The 'BUT' is that the displacement is driven by an image texture (made with the fabulous CrazyBump Beta program from the original image map). In order to get the cylindrical mapping to work in TG2, I have to set it to tile x & y with the values 0.5 to 750 ( I mean -why?!!!). This creates a horrible stripey texture on the surrounding terrain as you can see...

So the question is how do I set the image map and displacement maps to 'fall off' outside the diameter of my crater, so that they don't affect the surrounding terrain. And then how do I apply different textures to the surrounding terrain without affecting the Hoodoo?

I get the feeling the answer is incredibly simple, so if anyone wants to make me look stoopid, now's yer chance.

[peejay]

This time using a cylindrical displacement map without the image map and creating the formations by intersecting crater shaders with a Fake Stone shader with stone tallness of 0.01 so the stones don't show up outside the perimeter of the craters.

Apart from the problem mentioned previously about restricting the action of the displacement shader, this method could be improved if there was a way to increase the number of sides of the fake stones - is there?

[rcallicotte]

I haven't experimented with this yet, and it looks fun, but I'm guessing you'll need to use a Surface Layer and set your boundaries for height and / or slope.

[peejay]

thanks calico but that won't cut it if I have a hoodoo next to a cliff face or butte/mesa of similar height (which is pretty much where I'd expect to find them)