Ridge and Gully masks for populations

Started by Matt, January 19, 2019, 08:55:17 pm

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Matt

January 19, 2019, 08:55:17 pm Last Edit: January 20, 2019, 01:53:32 pm by Matt
Tip of the day: Although "Intersect Underlying" doesn't work for distributing populations [EDIT: actually it does, but is tricky to set up], you can create your own "favour rises" or "favour depressions" masks using just 3 nodes. Simply subtract "Get altitude in texture" from "Get altitude". This measures how much the terrain rises above a smoothed version of itself. The smoothing scale is determined by the "patch size" in the Compute Terrain node. To select depressions/gullies instead of rises/ridges, swap the inputs to the Subtract node.

Bonus tip of the day: Rock populations are an easy way to create distant vegetation without fiddling about with more complex objects and materials.

CORRECTION TO SCREENSHOT: The setup should use a Distribution Shader V4, not a Surface Layer, because the distribution shader's colour defaults to white (1). If you don't care about the altitude and slope controls you can just pipe the blue nodes directly into the populator.
Just because milk is white doesn't mean that clouds are made of milk.

Dune

I like these tips, Matt. Once a week?

I've used fake stones for distant veggies, which works neatly as well. And also used displacement intersection of a surface layer, with a black surface layer before it in a sideline to produce some kind of mask. But your tip really neat! Thanks!

archonforest

Weekly? Matt said Tip of the day....khm...so now... :P

Anycow, this is a great idea. Can we keep it?
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StephB

Thanks for this tip, very useful I'm sure!
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Hannes

Cool! Thanks, Matt!
Can't wait to read your next tip tomorrow! ;) ;) ;)

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mhaze

That is brilliant - it will be extremely useful.

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Shigawire

Love this! Working on a scene currently where I needed to do this in fact. But I already managed to mask populations by using the Erosion flow maps from Daniil's plugin, modified by altitude and slope and all that good stuff.

This is potentially much faster and more efficient.

Matt

Quote from: Dune on January 20, 2019, 01:56:03 am
I like these tips, Matt. Once a week?


I make no promises ;)

Quote
I've used fake stones for distant veggies, which works neatly as well. And also used displacement intersection of a surface layer, with a black surface layer before it in a sideline to produce some kind of mask. But your tip really neat! Thanks!


I couldn't get the Surface Layer to work with Favour Rises or Favour Depressions, which prompted me to try this new approach. I didn't try Displacement Intersection, but after seeing your comment I realise that all three options work if you provide them with a suitable terrain input and an intermediate black layer. But that's a lot to remember to set up, and slower to compute.

Now I realise that with a small change to the code I can make Favour Rises and Favour Depressions work without an input, so I'll probably fix that in the next build.
Just because milk is white doesn't mean that clouds are made of milk.

Matt

Quote from: Shigawire on January 20, 2019, 12:29:43 pm
Love this! Working on a scene currently where I needed to do this in fact. But I already managed to mask populations by using the Erosion flow maps from Daniil's plugin, modified by altitude and slope and all that good stuff.

This is potentially much faster and more efficient.


Yeah, this might be faster and easier to use, but you're likely to get more realistic results from proper erosion flow maps.
Just because milk is white doesn't mean that clouds are made of milk.

Matt

CORRECTION: The setup should use a Distribution Shader V4, not a Surface Layer, because the distribution shader's colour defaults to white (1). But if you don't care about the altitude and slope controls you can just pipe the blue nodes directly into the populator.
Just because milk is white doesn't mean that clouds are made of milk.

pokoy

That's very useful. Thank you!

There could be a sticky thread with all the tips of the day combined, each having another thread discussing the tip separately.