Noise filter masks

I’ve made a crater in a biome (absolute2(sum2d(Ditches+constant2d)). Now…around those craters I want to have hills, forests etc.

However, when I combine this crater with e.g. angled hills or whatever, the crater itself gets messed up. Of course I could use ‘min’ or something, but then I don’t get the hills. Is there a way of say…masking a noise filter so that the crater will stay intact but that the hills will spawn around the shore? I guess making my own noise pattern as a picture would work, but I’m wondering if there’s another way of doing it.

Thanks!

It’s difficult to do if the crater is a different biome than the hills/etc surrounding them (because you’re constrained by the biome size & how biomes blend.

One trick is to place the craters in an existing biome, and use a lerp node to effectively choose between the base biome terrain & craters (worley noise does a good job of creating sparse circular patches)

Thanks!. Yeah I was doing it in the same biome as I didn’t want to have the blending. What exactly does the lerp noise do? I can’t seem to get it to work.

I guess what I want is something that says: 'take all the negative value from map1, and combine it with map2, but ignore the coordinates of map2 which overlap with map 1

Lerp lets you use a noise function to choose between two other ones (and interpolate between them, if you like). The rivers function is a good example of it (albeit pretty complicated since it’s a custom node).

Here’s a quick custom node that’ll do it: https://github.com/turbulenz/boundless.worlds/pull/13 (and direct link to the node definition)

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Thanks! I’ll have a look at this after the weekend!
Are you a developer of this tool or just very very well accustomed to it? :slight_smile:

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Been playing with it a ton :slight_smile:

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I downloaded the rivers, and opened it as a node so I could follow what’s going on with each additional action, but whenever I press the blue button at any of the processes, I don’t get any heat map whatsoever. Anything I’m doing wrong or is that normal?

Ah, so, because I expose some of the nodes as options, you can’t preview from the main nodes - best bet is to use the preview nodes (bottom expando on the root node)

Or, while playing around, attach some noise to the low/high functions on the lerp node