Virgelle, MT Project - Terrain Strata help needed

[billg60]

I have been trying learn to use TG2 for about six months now (hundreds of hours, just ask my wife). I seem to make some progress and have learned a lot from the  posts here but I have hit a wall in progress with terrain  - so I turn to the community for some help. My project is to build an image for a backdrop for my model railroad. The possibilities TG2 offers is really exciting for the hobby as this is common place people have trouble if they are not very artistic (like me).

The project is a real place in the tiny town of Virgelle, MT, USA. The geography is interesting as the towns is near the Missouri River and on the other side of the river are sheer sedimentary cliffs that are about 60m high along with rolling grazing land. I have included a couple photos of the location to illustrate what I am trying to achieve. The view of the cliffs in my application will be from 800m away and 50mm camera lens so extreme detail is not necessary. In the .tgd file I have provided (.tgd and .ter is at http://www.terragen.org/index.php?action=tpmod;dl=item554),  I have moved the camera in for a close view of the cliffs but in the final view the cliff will be off in the distance only about one fourth of the image height. I will be stitching a 180 degree panoramic for the model for the backdrop image.

I have started my terrain with a DEM of the area. The key aspect of the terrain that needs assistance from the DEM topography are the cliffs themselves as they are steeper than the DEM resolution can pick up and they have sedimentary geology I want to simulate. I have applied S&O and a bit of displacement blending with a distribution shader to limit the strata to the narrow band like in the real cliffs. I have modeled my general approach from other posts regarding S&O but perhaps there is a better way.

I certainly welcome any general advice but a specific question I have is if there is a way to alter the vertical striations in the S&O layers. As shown in the photos, the real cliffs do not really have these.  I have played with octaves and depth but do not really seem to be able to make any difference. Secondly, in the PF that following the S&O node, I have manipulated many settings but can't seem to make any displacement show up, whatsoever. I am thinking that displacement is the approach to alter the default surface provided by the S&O node.
Thanks for any help you can provide.
Bill

(.tgd and .ter  is at http://www.terragen.org/index.php?action=tpmod;dl=item554)

[Dune]

I can't help you on this, but I'm sure others can. Anyway, this should be in 'discussion',  I guess.

[Henry Blewer]

There is a post on strata variation which can be found here. This might help out.

http://forums.planetside.co.uk/index.php?topic=9181.msg97637#msg97637

Another thing which may help break up the strata a little or a lot is to use a power fractal in the 'blend by shader' input at the bottom of the strata shader. Changing the scales and the color will make this power fractal into a mask.

[TheBlackHole]

Maybe use a power fractal for displacement? Stretch a PF by x3 y1 z3 or something. Play with the scales and displacement until you have nice-looking strata, then use another PF as a blend by shader.

[FrankB]

I had a quick look at your scene. The vertical striations are because of the powerfractal, that is streched on one axis by 100.
Try to temporarily disable this powerfractal and you should see these striations go away.
In order to make your strata look more like in the photo, you need to reduce the layer depth in the strata shader, and also reduce the hard layer spacing. Also 10 octaves are enough. Try to use the default values for the other parameters in this shader (plateau etc..)

Lastly, your power fractal does indeed displace the wall, but it's hard to notice, because a. it's streched a lot and b. the size and displacement values are relatively small.
If you would like to give more variation to the vertical wall, I would use a redirect shader (plugged into a surface shader with altitude and slope constraints) instead. Then plug two power fractal into the x and z shader input of the redirect shader. This gives you more control over wha's happening and where

Frank