Create a tree/vegetation mask

Help! How do I...
#1

I need some help creating a realistic tree and vegetation mask for an existing height map. I have the original WM files that generated the terrain, the heightmap, biome mask, snow mask, erosion mask, river mask and beach mask.

I’d like for realistic forests and outcrops of trees to be able to generate on my map I am making for Minecraft but cannot seem to figure it out, I’d be willing to hire someone to complete the task or help me figure out how to do it. I have WM Professional edition.

#2

@Charm8er You have to think in terms of how vegetation grows in nature. I can only outline a general workflow, it has to be customized on a case by case basis, depending on what type of terrain it is, resolution limitations etc.

  1. Let’s assume the goal is to create a mask, that you can use within your render engine where you can scatter vegetation. The first thing you need to create is a slope selector. Plug in your “Heightmap”, and very generously select wherever your preferred type of vegetation can grow (usually any slope from 0-35 degrees, though tall trees need a tighter slope range. Also try to keep falloff minimal). Now that you know the max cover your trees can cover, it’s time to start removing chunks from it.
  2. Now add a height selector, plug in your height. Select the max range your vegetation can cover, and be generous about it too. Same as slope, try to keep falloff to a minimum. Now plug the output of this height selector into mask input of the slope. Now you have a max slope cover your vegetation type can take.
  3. Add a combiner node, and set it to subtract at full strength. Name it subtract, since we’ll be copying this node again and again. Plug in your max masked slope into the first input of this node.
  4. Now all you need to do is subtract any area you don’t think your type of vegetation won’t grow, by plugging your compound “NO GO” mask to the second input of this subtract node. If you need to subtract multiple areas like rivers, wetness, and beach, just add them all at full strength, and then subtract it. If you want to expand the “no go” area, blur that mask a little, and use bias/gain to expand your no go mask (faster to process than expand node).

I’ve been using this method to create my grass and soil covers for over a decade now. Hope this helps somewhat! Good luck!

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#3

So I managed to get some masks made up, but I cannot figure out how to get them exactly how I want. I did what you described and then I used a directional selector to try to make the vegetation heavier on the north side of the hills and mountains. It works but I’d like for the difference between the south and north sides to be greater. Is there a device I could add that would increase the disparity between the north and south sides?

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#4

The stronger you want the impact of a directional selector, more the priority it needs to have among the sea of combiners. Best to subtract the inverse of directional selector LAST.
Try out this method. If it doesn’t work, dm me the project file with instructions, would be easier if I can experiment with it a bit.

Edit: Forgot to mention, you can also add a “bias/gain” to strengthen and sharpen any selector, though it may or may not work to a full extent if combination isn’t done right.