Inclusive mode determines how adjacent face corners are handled during selection of a face or edge. With inclusive mode off, selecting a face or edge only selects face corners directly involved with that face or edge. With inclusive mode on, selecting a face or edge also selects every face corner touching any of its vertices, even corners that belong to a different face.

This may be useful when selecting geometry for the purpose of assigning vertex colors or other attributes when smooth interpolation is desired with adjacent geometry, rather than creating sharp edges at face boundaries when modifying attributes.

This setting only affects new selection actions. Toggling it has no immediate effect on the current selection. To modify an existing selection, you can use the Select Special submenu items "Expand to adjacent face corners" to select all face corners touching all selected vertices, and "Shrink to selected faces only" to deselect all face edges not involved in a fully selected face.