Hi everyone!

I've got a situation where I need to make a large area of terrain, with some areas at higher detail/resolution than others. I have three heightmaps, one covering, say, a 10x10km area, one covering a 1x1km area and the final covering a 100x100m area, all of the smaller areas are embedded in the larger one, giving a high resolution coverage of the chosen area while still providing coverage for the larger, outer areas too.

So my question is: How do I (preferably in Blender) create a terrain which combines these three 'levels of detail'? Of course I tried just applying the heightmaps as displace modifiers to 3 different planes and putting them one on top of the other, but it didn't look great! Is there a way to apply the three different heightmaps to the same plane with each one acting on its own small area?

Thanks!

[...] all of the smaller areas are embedded in the larger one, giving a high resolution coverage of the chosen area while still providing coverage for the larger, outer areas too.

I don't know if this is what you're doing already.

Since these levels will overlap each other, I would create a single 10x10 km heightmap in my painting program, paste the 10x10 km low resolution as bottom layer, then decal on top of it the 1x1 km and 100x100 m areas and position them appropriately.

What I mean with "decal" is that you simply paste the denser levels as layers on top of the low resolution level, and smooth out the borders of these layers so the transition between high-res to low-res isn't too noticeable.

Then merge all layers to a single one.

This would give you a single 10x10 km heightmap that you can load in Blender, displace a single high-resolution plane with it and then use the Poly Reducer tool to educatedly optimize the parts of this high-resolution plane that only get the low resolution parts of the heightmap.

With weight-painting you can select which parts of the mesh this poly tool will operate to its full extent.