How To Limit Where Generators Generate

Hello, I’m new to using World Machine. I’ve watched two series of tutorials so far, but neither one of them answered this question. I basically want to limit where certain generators can affect the overall world. I’m crafting desert terrain. I made some sand dunes with a Voroni generator with a Constant filter to limit their height. Then I made some mesas with Basic Noise and added some Erosion onto them. Then I used a Combiner to link them together. I tried all the methods of the combiner, and Average looks best. The dunes appear to berm up the edges of the mesas a bit. However, the effect from the Voroni appears on top of the mesas. Not a game breaker, as I can make it look like there are small dunes of sand on top of them that got blown up there by the strong winds of the planet.

Then in another node branch I added some land masses, some of which come to peaks in small mountain ranges. These land masses ramp up to be slightly elevated above the dunes. However, when I used a Combiner to link these land masses to the dunes and mesas, the same problem occurred. I used Add as the method this time, as it preserved more of the features of both node chains. The mesas on top of the land masses isn’t a huge deal, but the dunes on the land masses are. I want to make the land masses have a more rocky texture, so having the terrain shaped like sand dunes doesn’t really help when I go to texture this terrain.

Is there any way to limit the height that a specific generator can generate terrain up to? I tried to use a Clamp, not sure if that’s what it’s for or if I’m using it correctly. Nominally, I’d like to tell WM “Don’t let this generator generate terrain above 30m” or “Don’t mess with the terrain that the other generators created” or “Only generate terrain in this specific area I’ve masked off.” Is there any way to accomplish any of those things? My end goal is to have the dunes berm up along the mesas, and have them be segregated from the land masses.


What I think you’re looking for is the technique called masking. You were right to use combiners in this case, as that allows you to mix two terrains together, but as you’ve also explained, it gives you some weird mixing, and this is because you are not using masks.

First, how do generators work. They create a “random” terrain that goes on to infinity in the X and Y plane. It is not really possible to tell WM to just “not generate” terrain above a certain value, so I recommend to not bother doing so. Instead, see a generator as an “infinite terrain creator”.

But how to combine two generators then? Well, as said, masking.

Masking allows you to tell WM to put the terrain of generator A here and the terrain of generator B there. So instead of altering the generators directly, you are filtering the location of where their terrain becomes visible, using a mask.

Let me show you an example:

Here we have two terrains generated. One by the Advanced Perlin, the other by the Voronoi (and edited by the Clamp, set to Rescale). We see both terrains cover our world. Now, when we want to combine them, we will use the Shapes generator to create a simple shape. That shape, will be our mask.

We feed the output of the shape mask into the purple port of the Combiner. The purple port is the mask port. The mask port tells the device to only change the world on a given spot/location, being the mask. In this case, we want to combine the two terrains and I’ve set the Combiner to the Average method, with the strength at 1. First, let me show you what would happen if I weren’t connecting the Shapes’ output to the mask port.

The world would be 100% input B, which is the Voronoi terrain. Now, watch what happens when we connect the mask.

Only on the location of the mask, we now see the Voronoi terrain. This is because we tell the Combiner device to only show input B at that location. Below, I will overlay the mask onto the terrain, for clarification.

And as you’d expect, the mask lines up perfectly with the location of the Voronoi terrain.

If you want to add another type of terrain/biome, just create a new mask for it and combine it.

I hope this mini tutorial helped you :slight_smile:

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