How can I remove the top mesh whilst leaving the bottom one fully intact and as it was before?

Question

I'm following the blendrGuru donut tutorial and when duplicating the top half, the two meshes have remained as one layer. I hadn't realised and saved so I can't undo, regardless this is something I'd like to know how to fix anyway. I've used control L to select the top mesh to separate it but it remains linked by one vertex as you can see. I can only use rip to separate 2 of the edges from the vertex, getting an error when I try to rip the 3rd edge away from the vertex.

Deleting this top layer deletes the linked vertex for the bottom mesh too as you can see. How can I remove the top mesh whilst leaving the bottom one fully intact and as it was before?

Answer 1

As far as I can see in the screenshot, the vertex connected to the top mesh is originally from the bottom mesh and moved up there, the bottom mesh is already broken there. No matter what you do, the vertex is missing in the bottom mesh and won't fall back in place anymore.

However, what you could work is you select this vertex and press V, this separates it into two vertices - one belonging to the top mesh and one to the bottom. But you have to move it manually back in place. After that you can delete the top mesh.

Or you delete the top like you did, then select the edge of the hole in the bottom mesh and do Face > Grid Fill. But this will not exactly recreate the original mesh either

Another possibility: if the above mesh is an exact duplicate of the one below (and not rotated, scaled or anything), you could recreate the original mesh. Go to Face Select mode, select the 4 faces that are missing in the bottom mesh. Set the Snapping Tool to Vertex. Duplicate the selected faces with Shift+D and move it down until it snaps into the correct position, so that all edge vertices sit on their corresponding counterparts and left-click or hit Return to place it. Delete the top mesh, then select all with A, then M > Merge > By Distance.