Author Topic: Power Fractal Color vs Displacement  (Read 222 times)

Offline FlynnAD

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Power Fractal Color vs Displacement
« on: June 14, 2017, 01:11:14 AM »
Hi all,

It's been a long time since I used TG and so my knowledge is rusty. Am I misunderstanding the natural way displacement of a PF works?

If a terrain with a base color (say orange) is input into a PF, and the PF has only an Apply High Color checked, so that the PF is "clear"
where the low color would be (so that the orange base color is passing through), if the PF's Displacement is applied,
that displacement does NOT seem to be linked to the PF's high color boundaries. Rather, it seems that the PF's displacement ends up over the entire surface, even where the PF itself has no color (where its low color would be).

Is this the natural way it works?

It would seem logical to me that the PF's displacement would be created from a grayscale value of the PF's Colors,
so that if the PF did not have a High or a Low Color applied, the PF's displacement would be blank at that point,
and when the PF's color was white, the displacement would be the maximum value of the Displacement amplitude,
and when the PF's color was dark gray or black, the displacement would be reduced down to zero.

Does it NOT work this way?

If not, how do I need to connect the nodes in order to create this type of logic? Use a Displacement Shader node? Mask the displacement somehow with the same PF color node?

Thanks,
Matt

Offline cyphyr

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Re: Power Fractal Color vs Displacement
« Reply #1 on: June 14, 2017, 04:21:14 AM »
Always worth (if you can) posting the scene file bit my first thought here is that colour information is not passed through a compute terrain node. Try disabling the Compute Terrain node (highlight and press d) and maybe the Base colours node and you should see you colours as you expect.
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Offline Dune

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Re: Power Fractal Color vs Displacement
« Reply #2 on: June 14, 2017, 05:38:56 AM »
It's an interesting question, as I have often wondered about that (even after all these years). They don't seem consistent indeed. I know that both colors and displacement work independently from eachother, so you can use either, and I have learned that if I want the colors to match displacement, I need to use the colors through a displacement or vector displacement shader (a.o.). If using color through a displacement shader, you need to work on the color roughness not to end up with a lot of spikes. And the low color can be a negative as well, of course, either clamped (for flat bottom) or unclamped.
Taking just the displacement (and its fine-tuning variables) from a pf can work through a displacement to scalar blue node (and a smooth step, or color adjust, e.g.) if you need to derive masks or colors from it.
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Offline Oshyan

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Re: Power Fractal Color vs Displacement
« Reply #3 on: June 14, 2017, 06:39:33 PM »
High and Low colors have no relationship to the displacement output, they are separate and for color output only. The Displacement tab controls the displacement, though of course any controls having to do with the actual characteristics/nature of the noise such as roughness, octaves, etc. do affect displacement (as well as color) output. If you want the displacement to only show up in a particular place, you should Mask the Power Fractal.

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