Comprehensive Rules
704.5u
If a permanent with space sculptor and any creatures without a sector designation are on the battlefield, each player who controls one or more of those creatures and doesnât control a permanent with space sculptor chooses a sector designation for each of those creatures they control. Then, each other player who controls one or more of those creatures chooses a sector designation for each of those creatures they control. See rule 702.158, âSpace Sculptor.â