As for boolean operations: that would require manifold ( a.k.a. 'watertight') shapes, so meshes in which each facet edge meets exactly one other facet edge. For non-manifold objects you cannot say what is 'inside' and what is 'outside' of the mesh. Meshes of objects in Poser in general are not manifold. If you have ever tried to 3D print a Poser figure you will know what I mean.