Combine two weightmaps

this this a very base terrain, i combine two shapes and use smooth max way.when i try to make some weightmap for them, i get stuck. i just want higher area weightmap cover lower weight map, but i do not know how to do that,any one can help me?thanks


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You must keep track of the differences you create when combining the two. You can do so by using a Combiner[Absolute Differences] + Select Height device. Then use that mask (and the inverse of it) on the appropriate selector device.

That said, why not do it like this, which to me, makes a lot more sense.


Now, a wetness and slope mask is created for all of the terrain at once, no need to mask afterwards.

An even better approach (in my opinion) would be this:


From what I can see, your main difference in erosion appears to be the hardness setting for the terrain, and if that is true, you can use the “differences” mask to control the hardness of the terrain, influencing the erosion rate. Since you will be using only one erosion device, the two terrains will blend a lot better.

EDIT
And now with the file!

differences-selection-example.tmd (281.3 KB)

thanks bro, i tried absolute differences node, is useful and save my life,by the way,this way that you showed is make weight map in worldmachine,if i want import the weight map from other terrain software, i mean totally made by other software, worldmachine just input heightmap and weightmap,do you know how to combiner their together?

Hmm. In the context of 3d modelling, I know what a weightmap is but I’ve never heard of their use on a terrain. Is this a game related practice? What exactly do you use them for (if someone would be so kind as to explain it for me)?

@davidroberson Weightmaps, masks, channel masks are all the same thing. It’s a black and white mask you can either export from wm as a separate weightmap, or as an RGBA image, containing 4 such weightmaps (also sometimes called a SPLATMAP) as individual channels of said image. This can later be used to set up your material, or to scatter vegetation etc, in a game engine or 3D program.

For example, this one. I used masks/weightmaps exported from wm to build this material (though I did it inside wm itself, but could have been done the same way in blender).

Hope this explanation helps!

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Ah. I was thinking of weightmaps like you use in rigging 3d models. That use of the term just caught me off balance. Thanks for the clarification.

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Yeah they are simply “Maps describing Weights of something”. Term could be used anywhere really. Just here, the context is erosion masks etc.

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Glad to hear the absolute differences method works!

I don’t use weightmaps myself and always go for individual masks, so I can’t really help with this :confused: I suppose you could have one mask take precedence over the other? Just like you do when using the differences mask to combine the wetness mask, but again, I never use such a workflow so this is just me telling you what comes up in my head :wink: