Procedural Generated co-ordinates issue

Hey guys,

Can someone help me here. Problem is ive got a massive terrain that i want to break into sections after sculpting. I can sculpt a high res 50 million poly terrain in sculpt mode with multires, I then select groups of faces from the mesh in edit mode and separate to selection.

This then gives me separate mesh’s with their own multires still applied and which holds the original sculpt data, this means that all separated sections match on edge vertices. Idea being i can then render out a 16 bit height map for each separate section and combine the tiles in photoshop to generate a massive terrain height map.

Problem is ive got a shader on the mesh sections with generated co-ordinates that run into a gradient texture and then into a color ramp node and finally into diffuse shader. This gives you a black to white height of the object from lowest point to highest point on the Z axis of the object.

But when you separate each section and bake the texture the maps dont match anymore, Im guessing once separate objects the generated co-ords are changed. Is there a way i can say create an object like a cube for example and then set this object as the generated texture co-ordinates generator? This would mean each separate object would have a set black to white point and all tiles would match.

Any ideas how to solve this?

Use another coordinate system that is commom to all the pieces.
The World Coordinates it’s probably the easiest (Geometry>Position), but you can also use a texture space from any other object (TextureCoordinate>Object and peek the common object on the bottom).