Merge To Center merges
any selected vertices so they become shared and positions the resulting
shared vertex at the center of the original selection. Any faces
and edges associated with the originally selected vertices also become
merged as a result.
NoteThe
Merge
to Center feature merges to a central point based on
the center of the current selection. If you want to collapse edges
on a component by component basis, select the edges, then select
Edit Mesh > Collapse,
or shift + right-click and choose
Merge/Collapse Edges
> Collapse Edge from the marking menu.