Author Topic: Terrain displacement over objects  (Read 385 times)

Offline sboerner

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Terrain displacement over objects
« on: November 06, 2018, 02:49:01 AM »
When you feed a masked power fractal through a transform input shader (worldspace enabled), and then tie that into an object's shading group and the scene's surface layer, the color overlaps both. But not the displacement.

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I'm guessing this approach is too simplistic but I'm not sure why. The cube has 10,000 polys per side so there's plenty of geometry for the displacement to work with.

Offline Oshyan

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Re: Terrain displacement over objects
« Reply #1 on: November 06, 2018, 04:24:51 AM »
Do you have Force Displacement enabled for the object rendering method?

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Offline Matt

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Re: Terrain displacement over objects
« Reply #2 on: November 06, 2018, 07:12:08 AM »
You'll need to use "Force displacement" on the "Render" tab of the object. However, force displacement works more efficiently with objects that don't have so many polygons. It uses the rasteriser rather than the ray tracer, and it subdivides polygons automatically. You're better off with a low-res cube, or the built-in Cube primitive which is a natively displaceable object.

Matt
Just because milk is white doesn't mean that clouds are made of milk.

Offline WASasquatch

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Re: Terrain displacement over objects
« Reply #3 on: November 06, 2018, 07:37:51 AM »
Is that why high poly objects get a kinda super rough displacement result full of spike? It's basically over-subdividing?

Offline sboerner

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Re: Terrain displacement over objects
« Reply #4 on: November 06, 2018, 02:23:26 PM »
Thanks Matt, Oshyan. That was it. Will make a mental note to check that setting from now on. And thanks for the clarification re: low- vs. high-poly objects. That was another thing I was wondering about.

Offline sboerner

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Re: Terrain displacement over objects
« Reply #5 on: November 07, 2018, 05:53:32 PM »
So this is where I was heading with this I'm looking for a way to create natural wind-blown snow on top of placed objects. This is very quick and basic. It uses two SSS masks, a hard one for color and a soft one for displacement. But the boundary is noisy and doesn't look right. And I'm not sure how well this technique might work with irregular and oblique surfaces. Can't decide whether I should pursue it further or just file it away as a dead end.

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Offline Dune

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Re: Terrain displacement over objects
« Reply #6 on: November 08, 2018, 06:00:11 AM »
That would work alright, but it also depends on the polycount of angled areas, where you want no snow.

Offline WASasquatch

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Re: Terrain displacement over objects
« Reply #7 on: November 08, 2018, 07:43:36 AM »
That would work alright, but it also depends on the polycount of angled areas, where you want no snow.

Wow Ulco, that's a really good example, angle are almost there.

Offline sboerner

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Re: Terrain displacement over objects
« Reply #8 on: November 08, 2018, 02:02:43 PM »
Thanks for that example, Ulco. I was thinking that this might work better with large-scale objects instead of small ones. (And having an actual model helps, too.  :D ) It should be fairly easy to make accurate object masks with an overhead orthographic camera, and to do them in large groups. Gives me some ideas.

I've spent the past week recovering from minor surgery and have been away from the desktop workstation. So I've been using the laptop to mess around with small scenes, combing through the forum and downloading files, looking up answers to some of the questions I still have. There's a wealth of information here. It's been time well spent.