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Blending a realistic landscape material with PBR textures

I'm trying to blend a realistic landscape material, that combing rocks, dirt, grass, etc. What do I do with the ambient occlusion textures? And how do I blend the displacement textures? Both don't seem to go anywhere.

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    $\begingroup$ Multiply each of the AO textures over their respective BaseColor textures using a MixRGB node. and mix the displacement textures using another MixRGB node, this time, use the same mask as a mix factor as you're using for your mix shader mix factor (for example, combine the first 2 displacements using the first colorramp as a factor, then mix that result with the next displacement using the second colorramp as a factor). $\endgroup$ Aug 27, 2022 at 4:25
  • $\begingroup$ Thanks. Now I understand the part about combining the AO textures. Could I get a picture of what to do with the displacement textures? $\endgroup$ Aug 27, 2022 at 4:48

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If you mix multiple shaders, each with their own displacement, you can just mix the displacement vectors with the same fac that you mix the shaders. Displacement output is a vector, but it's fine to use a MixRGB (unclamped) to mix between vectors, since there isn't a "vector lerp" node:

enter image description here

You'll notice that every displacement map may demand different settings for midlevel and scale.

Cycles doesn't have a conception of ambient occlusion, because there is no ambient lighting in Cycles; it's all sourced, even if eventually to a world sphere, and it's all occluded by geometry, unlike game engines that use unoccluded ambient lighting. Ambient occlusion is a technique to mimic the occlusion provided by high-poly local geometry on a low-poly proxy. In this case, where you're using true displacement on high poly geometry (perhaps via adaptive subdivision), you don't need or want to use ambient occlusion textures in your materials. Any technique you'd use to do so would be double dipping, occluding once via geometry and then again via your texture.

In Eevee, there is some limited support for ambient occlusion maps in the Specular BSDF node. If using low poly, game-engine models with AO maps, it's often appropriate to build your materials around that BSDF rather than the principled BSDF.

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Here - just posting so I can post the picture - I made a (simplified) facsimile of your setup and included the displacement mix - the displacement section is highlighted at the bottom. Make sure to test the mixes independently first, because sometimes top/bottom position of the input connection can be backwards depending on how you want your mix to be:

DisplaceMix

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    $\begingroup$ I also find the question interesting, but your answer, which I am convinced leads to the goal, I unfortunately do not understand at all because of the small colorful picture. I find it hard to see what is what and the color confuse me quite a bit. Can you please explain this in more detail? $\endgroup$
    – quellenform
    Aug 27, 2022 at 8:41

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