Attach geometry to other geometry without duplicating it I have this mesh:



I'd like to copy the highlighted vertex group to the other end of the mesh, here:



I've duplicated (shift-D) the selected vertices and moved them to the other side by grabbing, until I got what I wanted:



Anyway, the resulting object is made by 2 different objects which can be separated with separate by loose parts.
How can I attach the object to the final point so that they're only a single object and cannot be separated (one single geometry)?
Thank you

EDIT: the underling vertex geometry to both top and bottom is the same
You hit on the first one which is using separate.

Once you move the separated object into place (you can control this with extreme accuracy if you are using snapping methods for vertices / edges in this particular case), you can use JOIN.

To use the command:


Select the pyramid textured cross.
While holding SHIFT select the extruded cross shape.
Finally CTRL + J will perform the join operation.


To clean up the operation:


TAB To enter into Edit Mode.
A To Select all Vertices.

a. NOTE: CTRL + TAB >> V if your selection mode is NOT set to Vertex.
W >> R to remove redundant vertices.