create a terrain from a power fractal, plug a compute normal shader into it and then set the displacement to lateral only. This is your hidden terrain.
Now create a second terrain, any style you please - in the attached shot it's a basic perlin billows based rolling hills landscape. This is your visible landscape.
Now plug a crater shader into your hidden landscape with a large negative depth value, and the crater shader will 'push' the hidden landscape through the surface of the
visible landscape to create something like these.
Anyone who's good at maths and node manipulation care to take this further to see if it's possible to get decent rock stacks and towers out of this?
Cool. Thanks for explaining.
this is what happens if you change the node order.
(edit)
or more precisely, using the same file this:
the towers are looking much better but the visible terrain is cracking up
After I get through some stuff today, I'm going to play with this.
Looks like the start of some hodo's?
OK, here's how the white tower rendered. Bits of it look promising - could make a cool sci-fi planet maybe, but the base is just wild. Plus, I have a sneaking feeling this is actually rendering inside out somehow, in which case once back face culling comes along, it might not work at all. Anyway, here's the tgd for those who like to play (and hopefully have better brains than mine)
good luck one and all....
Wouldn't have to be SciFi. Check the image here: http://tinyurl.com/yr3n3e
nice pic jaf.
Yes, hoodoo's is what I'm after, in fact the inspiration for this line of enquiry was a desire to replicate a pic I saw of Bryce canyon, but the whole thing needs to be 'calmed down' a bit in order to be believable. I can't do it because I don't understand what TG2 is doing, therefore it's trial and error which settings will affect the terrain in the way I wish. I'm hoping someone who actually 'gets' this program can pick up the experiment and knock it into shape ::)
Yes, I've tried making some 3D models in Lightwave and finishing them in 3D-Brush. But your method may be better and faster.
Funny, I first saw the name "Hodo" several years ago but then when I did a search I couldn't come up with that many images. But "Hoodoo" definitely solved that.
all adjustments on the crater shader:
basically decreased (or should that be increased) the negative depth value, increased the rim height, and set the rim softness to 0. That seems to have stopped the base rocks poking through each other.
The lateral displacement is still far too extreme in the base of the tower. (must go and explore the weird domed hills on the left :))
EDIT:
well they're even weirder than I thought; check this out..
Something i just found out while playing with this: Increasing the patch size of the compute normal node will decrease the ugly crack effects.
I'm doing a lagre-scale render now to see if this technique can be used to create interesting shapes on normal terain. Havn't tried using it with an inverted crater yet.
Also, the smooth terrain checkbox can be a friend...
"I'm doing a lagre-scale render now to see if this technique can be used to create interesting shapes on normal terain."
well spotted virex; something like this 'cliff house' for example?
This was produced with a perlin billows fractal in the hidden terrain,
feature scale: 427
lead in scale: 25000
smallest scale: 2
Displacement: lateral only
Displacement amplitude: 10.0113
Displacement offset: 198.854
Displacement roughness: 0.86785
Noise variation: 10
Multi Scale modulator
Buoyancy from variation: 3
Clumping of variation: 3
visible terrain:
perlin billows
Feature scale: 5000
Lead in Scale: 25000
smallest scale: 0.1
Displacement: Along vertical
Displacement Amplitude: 15.2588
Dispacement offset: 0
Displacement roughness: 0.45625
Displacement spike limit: 0.19375 (Continue spike limit checked)
Noise variation: 30
Multiscale modulator
BUoyancy from variation: 2
Clumping of variation: 5
Distort by normal: 5
1 Ocatve Perlin warp
Lead in warp amount: 0.75
less warp at feature scale
to show the variety of forms that can be achieved, all be it in a very haphazard way.
Again this is two terrains, one with displacement set laterally, the other vertically. This time the hidden terrain is modified with a power fractal on x & y axis via a redirect shader.
Does anyone understand what is happening here? More to the point - how to control it?
anybody? anyone at all....
Here's another example. I'm rendering it with an even higher patch size and some other tweaks now.
I've messed with this a little today, but found that moving the camera will blow up TG2. I've stopped experimenting for now.
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.
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.
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?
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. ;D
Quote from: peejay on March 03, 2008, 11:20:07 AM
calico - I haven't had any problems with the camera other than finding myself inside a massive displacement.
This looks promising ... I have absolutely no time ... but ,-)
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
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)
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.
;)
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?
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.
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)