Change the flags of a building sub mesh in asset editor.

Flags_BuildingSubMesh.cs

var subMesh = 0; // sub mesh id, order as in ui, starting from 0
var asset = ToolsModifierControl.toolController.m_editPrefabInfo as BuildingInfo;

// required and forbidden flags, use | to set multiple flags
asset.m_subMeshes[subMesh].m_flagsRequired = Building.Flags.Created | Building.Flags.Active;
asset.m_subMeshes[subMesh].m_flagsForbidden = Building.Flags.Abandoned;

// all building flags:
/* 
	None
	Created
	Deleted
	Original
	CustomName
	Untouchable
	FixedHeight
	Incoming
	Outgoing
	IncomingOutgoing
	CapacityStep1
	CapacityStep2
	CapacityFull
	RateReduced
	HighDensity
	LevelUpEducation
	LevelUpLandValue
	RoadAccessFailed
	Evacuating
	Completed
	Active
	Abandoned
	Demolishing
	ZonesUpdated
	Downgrading
	Collapsed
	BurnedDown
	Upgrading
	Loading1
	Loading2
	SecondaryLoading
	Hidden
	EventActive
	Flooded
	All
*/