I’m using a height map from a real lake, but the texture thinks the terrain stops where the lake is. How can I lower JUST the lake part and not effect the height of any other area?
I’m looking at this just before bed, so I might have a better idea in the morning when I can properly think about it, but my first thought is that since it’s perfectly flat, if you were to open the heightmap in a program such as Photoshop, you could use the magic wand tool to select just that area, and manually change the height with different shades (such as filling it with flat black to zero it out if you want), or fill it with white, invert the selection, fill the rest with black, and use the resulting image as a mask for the original, then use filters to adjust to your desired height (though if you go that route, I’d either blur the mask, or use feathering when creating it to avoid harsh edges).
You cannot lower the lake further if it’s already at zero height, but you can raise rest of the terrain leaving the lake at zero. Here is a tmd file for wm 2.3.7 to show how.
The relief of the terrain won’t be affected unless you increase height too much.
If you want to do it all in world machine try using a slope selector that selects only really flat areas and mask that selector with a rough outline of the lake made with a layout generator.
Now that you have selected your lake apply thermal weathering erosion to the mask, not to the terrain istelf but only to the output of the slope selector, that thermal weathering should have a low mass balance and be very strong with lots of iterations.
Then subtract the output of the thermal weathering from the terrain using a combiner set on “subtract”.
Tweak the thermal weathering to your liking and don’t set the combiner value too high.
Now if you want your lake bed to look less uniform subtract an advanced perlin from the thermal weathering output