J_Meyer, the guys are right. Those differences are coming from different patch sizes. What may seem logical on first glance, is to assume nothing should change. But your initial shape is being triangulated by the patch sizes when you use a compute node, so triangulating different patch sizes on top of each other will yield different reference points depending on which order they are set. Drawing a triangle on top of another triangle so to speak.
I tend not to like using the displacement tab in a PF, I find it difficult to track masks when displacement happens on displacement. So I tend to stick in the -1..0..1 scaler range to build a pattern, then multiply that output by the amount of meters I want to move something.
Try this, turn the colour roughness in the "Fractal terrain 01" PF in a default scene down to 1. Make sure Apply high and low colour is switched on and displacement switched off, then multiply that output with blue nodes by a value that is equivalent to displacement amplitude in the PF with a Constant Scaler, in this case 2000. Then plug the result into a Displacement node, you should have more or less the same terrain as if you had created it with the displacement tab in a PF. The advantage here is that you have full control over how you want to mix or temper your fractals, noises, or SSSs.. at an early stage that can be read downstream later on. Its also a really good way of building terrain around a scene focus, like a road.
Now take the input of the previous Displacement node and plug that into the y of a Build Vector node. Plug that into the function input of a Vector to Displacement node, then plumb that into your Base colours node attached to the planet. You should still have the same terrain as before. But now you have access to shifting x and z through y with another pattern via the Build Vector node x and z inputs.
Try multiplying another PF scaler (black and white) output with displacement turned off, apply colour on, roughness back to 1, and some tasteful scales, via blue nodes to a sensible size in meters and plug that into x of the Build Vector. Your terrain should now have shifted laterally in the x y plane, by the PF multiplied by meters. Notice that you haven't needed to use a Compute node to shift laterally. Cool huh?
This can all be done by displacement too, with a redirect shader as Matt suggested in the squared rock thread. Its essentially doing the same thing.
