I was wondering how to merge a head with a body when both are from different projects? I made a head in sculptris and went with GoZ which puts it into a new project where I added detail. I also have a body I made in zbrush and would now like to put both together and have a single model/mesh(?).
Save your meshes as Tools ZTL and load in the same project. THen you can append as subtools.
Once appended as subtools, fuse the meshes by merging them into the same subtool, and re-meshing via dynamesh or the subtool menu re meshing controls. Use projection to recapture lost form or detail. Once fused into a single contiguous mesh, use Zremesher to build a new low poly mesh for establishing multiple subdivision levels with any former detail.
http://docs.pixologic.com/user-guide/3d-modeling/topology/zremesher/transferring-detail/