ZBrushCentral

a question about blending displacement maps

I have been seaching for an answer to this and so far have had no luck.
What I want to do is animate something like bruce banner transforming into the hulk using blendshapes and displacement maps. As he changes I want to gradualy morph one displacement map into another. Imagin how his muscles would rip and become more difined and how his veins would bulge out. This is the kind of thing I’m going for and I’m thinking that I would need to blend from one displacement map to another as there is not enough geometry to do it all with blendshapes. I’m not sure what the prossess for this would be and am hoping that someone on here may know the answer.
I’m using zbrush 3.5 and maya 2010.