Some interesting reading on procedurals

[AP]

http://www.decarpentier.nl/scape-procedural-extensions

[Henry Blewer]

Great article. I found his insight very interesting.

[AP]

I wonder if Planetside could make any of this code useful for Terragen.

[Henry Blewer]

Actually, I thought that the method translates into Terragen 2 very well. I use ridged power fractals with the Y axis stretched to mimic erosion. I never thought about using a blend/distribution shader setup until I read this. Once again something 'clicked'.

[AP]

Actually, I thought that the method translates into Terragen 2 very well. I use ridged power fractals with the Y axis stretched to mimic erosion. I never thought about using a blend/distribution shader setup until I read this. Once again something 'clicked'.

I tried that a few times. It does not work for me. I honestly see no difference. Perhaps i am missing something.

[Henry Blewer]

Well, short of having an algorithm to create erosion; something like World Machine; this seems to be a way to get an erosion effect.

I have been trying out my interpretation of what the article talks about. I'll post the tgd and a link from here to the file in the file sharing section.

[Matt]

Well, short of having an algorithm to create erosion; something like World Machine; this seems to be a way to get an erosion effect.

We do have a heightfield erosion operator in TG called Heightfield Erode v3.

Matt

[AP]

Yes and it is quite versatile but slow compared to world machine and geo control. The faked procedural erosion on the link provides some neat possibilities i think.

[Matt]

True.

Matt

[Henry Blewer]

It works well Matt, but the fun part now is to create something that can be used with the Fractal Terrain generator. I think it can be done without the long calculation time required in heightfields. I think by limiting the altitude and slope this can be done.

The difficulty is getting the erosion runnels to blend down slope into the major erosion channels.

This is what I have so far.

http://www.flickr.com/photos/njeneb/6901639986/sizes/o/in/photostream/

It blends two power fractals (ridged and mix 2) using a merge shader. The slope is controlled by a surface layer. If I were just trying to make an interesting rock face, this is good. It is not what I am striving for.

[AP]

I kind of see a wide faked-erosion left of center. Now the real issue is getting narrow channels and tapering out at the base.   

[Henry Blewer]

I think the only way to do this is by image maps. I was watching Walli's video on importing heightfields into 3Ds and Lightwave. http://www.planetside.co.uk/content/view/58/27/  Slope images can be generated this way.

[Henry Blewer]

Tried something else here. The displacements after the fractal terrain node were masked by a low slope angle.

http://www.flickr.com/photos/njeneb/7050672749/sizes/o/in/photostream/

Different view.

http://www.flickr.com/photos/njeneb/6904660606/sizes/o/in/photostream/

[Kadri]

The second one looks very nice Henry.

[Henry Blewer]

The last images are close to what I had in mind. I think masking by slope will do the trick. I'm going to try using an Alpine fractal in a heightfield.