Zbrush: Dynamesh. Single sided object fill

MancD

Is there anyway to stop zbrush attempting to fill in these areas? It's a ma model imported in via fbx.

I'm thinking dyamesh doesn't like hollow geo, right? Is there  a way around this?

Ghogiel

Dynamesh will fill any holes in your mesh. solution is to either let dynamesh do it or if you want control over how the mesh is solved, do it yourself in max.

Epitaph

Shell modifier in max is your quickest solution

cryrid

I'm thinking dyamesh doesn't like hollow geo, right?

Correct. It is designed to work with "water tight" volumes only. This means any holes will be filled if you don't do it manually, and single-sided planes (or even super-thin volumes) will lead to other errors in the result (such as a "swiss cheese" effect).