I have a problem but haven’t found a good solution yet.
In Cycles I want to blend together two materials of an object based on the direction of the surface. All the surfaces that look upwards AND downwards should have Material A assigned to it, all the surfaces that are horizontal should have Material B assigned to them. The transitions should be controlled by a curve or color ramp.
This is how the model looks.
There are tutorials here about landscapes and assigning rocks, grass or snow to the surface depending on the orientation or height, but I didn’t find a solution for surfaces that point upwards AND downwards.