Displacement variety

[EmDee1]

This shouldn't be too difficult really, but I can't figure out how I can vary the presence of displacement over a terrain or within a specific surface layer.
I can achieve displacement over a whole surface, everywere the same, but I want to vary it in different spots on the terrain, so it looks more natural.
Tried image map shader, power fractal shaders, but I guess I'm not understanding quite what to do, not getting the sence where I should connect the nodes.
Maybe someone has a clue to get me on the right track?

[Virex]

You could try to start big, and work your way down from there. In other words, when doing the large displacements, up the feature scale and the lead-in scale. Then add more nodes, decreasing the scales and displacement as you go. That ought to get you some more natural effects. If you'r using fractals as blend shaders, remember to tick "Blend by shader" though, and do he same thing. Start large and work down.

[rcallicotte]

Use masking.

[dhavalmistry]

if you are using surface layer's displacement function, then you can limit the surface layer to slope/height or if you are using powerfractal, then you can use blending shader or as calico said...you can also use masking!

[EmDee1]

Thanks for all the suggestions. I know about blending shaders and masking, but they seem to have no effect; maybe I must make the displacements much stronger; so I mean: not displacement 1 or 10 but 1000 or more...

[nvseal]

Could possibly post an in image (a photo or render) of what you are trying to achieve and/or what you are currently getting?

[EmDee1]

Hi nvseal, included a small render of the image. My question is about the front part, the large field on the right. A lot has to be done of course, but as you can see, the displacement in that area is the same everywere. I want to get variation: some places more, other places none or less displacement.
There must be a way to accomplish that by means of an image mask or blending shaders, I'll give that another try tomorrow...

[rcallicotte]

EmDee1, this looks very good.  Maybe finding a way to add Surface Layers to sort of catch that layer and manipulate this layer through a created black & white mask...?  Not specific, but I can't see what you're doing.

[Virex]

What you could try is adding a distribution shader after your compute terain node, set it's max slope constraint to something low, and use a powerfractal (or several) with a reasonably large scale and a small amount of displacement as the child layer. I think using the perlin type called billows will yield the best result, but any of the mix types could also do well.

[moodflow]

Agree with Virex^

[moodflow]

Additionally, a great exercise to do is to start a default scene, add a power fractal with black /white colors, and play with the fractals via all the tweaks.  See what they do. 

Then you can plug this into any of your other shaders as a "mask" and get that diversity.  I have a feeling you are doing things right, but your scale is off.  Or maybe not.  But that's what threw me off in the beginning.  My scale was off.  Once I realized the scale I was working at, things fell into place.

[Tangled-Universe]

Additionally, a great exercise to do is to start a default scene, add a power fractal with black /white colors, and play with the fractals via all the tweaks.  See what they do. 

Then you can plug this into any of your other shaders as a "mask" and get that diversity.  I have a feeling you are doing things right, but your scale is off.  Or maybe not.  But that's what threw me off in the beginning.  My scale was off.  Once I realized the scale I was working at, things fell into place.

This is a very useful tip for EmDee Moodflow.
Almost exactly the same way I figure out my scales.

The way to vary the distribution of displacement can indeed be done via (image)masking, either image-based or powerfractal-based.
If you want to check the scales of your powerfractal you want to use to mask/blend your displacement with you can add a powerfractal, give it two contrasting bright colors, increase contrast and start playing with the scales. You can "measure" your terrain by using your mouse. Not really accurate, but it works fine. When you have found the right scale and variation simply switch the colors to black and white and use it as a mask/blend-shader. In some cases some tweaking is needed after switching to black and white.

[EmDee1]

What a great forum this is Thanks people for all your help and suggestions. They're very welcome!
I'm gonna study them and play with the settings as suggested.
Concerning the scale mentioned: indeed, I find that difficult to understand and work with.
Maybe that scale-issue goes for the camera point-of-view as well: in this particular image for instance I want to give the feeling, that the field and the small road in the front are not too far away from the spectators eyes, but when I look at the numbers in my preview-render-screen, the actual hight is more than 400 meters
Still a lot of things to solve then...

[Tangled-Universe]

...but when I look at the numbers in my preview-render-screen, the actual hight is more than 400 meters

This is no problem at all of course. It's all about perception. If it looks like it is close to the spectator but the scale INSIDE the program is ridiculous, who cares then
As long as it looks o.k. it doesn't matter whether the chosen scales are real-world based or not.

[Seth]

Additionally, a great exercise to do is to start a default scene, add a power fractal with black /white colors, and play with the fractals via all the tweaks.  See what they do. 

Then you can plug this into any of your other shaders as a "mask" and get that diversity.  I have a feeling you are doing things right, but your scale is off.  Or maybe not.  But that's what threw me off in the beginning.  My scale was off.  Once I realized the scale I was working at, things fell into place.

goddamn !!!
didn't think about it <shame>
thanks moodflow !