Cuando edit a complex surface in Blender that can be neceserio postteriormente tear it into smaller parts in order to assign materials , move etc..
The material allocation problem does not need this physical separation, since we can generate vertex groups and assign different materials to each group.
First. Edit mode, select the vertices corresponding to the part of the surface separated from the rest wish. Any vertex selection procedure is usable in this step.
With the vertices selected in edit mode will press the P key to get a context menu on screen; select “Separate” and then “Selection”