i have a couple of diplacement maps that correspond to some blendshapes….but simply piping out the P N output of one disp vop into the P N input of the next disp vop,gives very unpredictable results .does anyone have a better workflow for this

How are the maps intended to be combined? The validity of the technique depends on that which was used to create the maps in the first place.

If you want a summation of vectors, you need to add up the map values (the zero-centered raw values), and connect the sum to the value input of a displace node.

Chaining P,N in a series of displacement texture nodes will produce a different result.

Jonathan Mack