Use a heightmap as a terrain mask?

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1

This is a little bit of a strange one, but I created a map for my game in Wonderdraft. It’s a simple map, looks like any regular cartography map. It has no text or land masses or anything else inside it. The software has a height map feature, it exports it as grayscale and looks just like any other height map

I’m wondering how I can use this in Gaea, as a mask to shape my terrain. So let’s say I have a simple mountain range, did some erosion on it, just the basics. Now I want to use this exact shape and the outline of this continent, and anything that’s outside the borders should be completely flattened, as if it’s water

How would I achieve that?

RDT_20260611_0938047472704849622868952
RDT_20260611_0938047472704849622868952640×616 28.6 KB

2

generall some good nodes/modifiers for this kind of thing
/shaper
/tint
/blobremover
/threshold
/curve

Your goal is to separate and increase the contrast

  • You could blur it a tiny amount to remove the grunge
  • add a tint of black and white or defaults
    • 1 a shaper modifier
  • finally find the right threshold

For it to be a mask, then after you can run it through an RGB split node

edit: Just tested it, seems to be fine

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image1800×771 75.2 KB

3

Thanks Ty. How did you get it to flatten out like paper? When I bring it in, it looks like an island for some reason, and raises it high up

4

On import in the file node, I kept it as RGB, then converted it to a mask at the end using RGB split the outputs of that proved as a mask ( shown in the image)