Once I join a mesh, I don’t know how to separate out these polygons. I export to Zbrush which has this feature, maybe selecting based on texture one time, based on animation another time, or separating features I need to model, then import back the new groups. How do I change re assign grouping in Blender without having to click on each vertex (impossible with my current mesh and its complexity).
You can select unconnected meshes within an object using the L key. You can select by material with the “Select” button under Material on the Links and Materials tab in the buttons area. You can select by vertex group (if you’ve got them defined) in the same way, by pressing select under the Vertex Groups.
From the description of what it sounds like you want to do, you might also want to know that H will hide verts for when you don’t want to see them, and Alt-H will unhide them.
how do I split up a mesh so that each unconnected polygon in the mesh becomes a separate object?