Depending on the copied vertices, some faces may have copied over too. You can see an example of that with the two windows. Square faces for the windows copied over, but since you don't want stonework over your windows, you want those sections to be holes or cutouts. You first need to delete the unnecessary faces. The steps are as follows:
- If necessary, in Object Mode, right-click on the object to select it and switch to Edit Mode.
- Click on the Face Select icon and right-click on the face you wish to remove to select it:
Selecting a face to remove
- Click the Delete key on your keyboard. A menu prompt ...
