Constructor

Vanilla Constructor : Stackable, IConstructionKit at Assets.Scripts.Objects.Constructor. The held-item kit form for placing a single Structure prefab. Used by every "single-item kit" (kit-cable, kit-wall-frame, kit-airlock, ...). The companion MultiConstructor covers multi-prefab kits (rail kit with 8 rail variants, etc.).

Class layout

public class Constructor : Stackable, IConstructionKit
{
    [Header("Constructor")]
    public Structure BuildStructure;
    public int QuantityUsed = 1;

    public override void OnUsePrimary(Vector3 targetLocation, Quaternion targetRotation, ulong steamId, bool authoringMode)
    public virtual void Construct(Grid3 localPosition, Quaternion targetRotation, bool authoringMode, ulong steamId)
    public static Structure SpawnConstruct(CreateStructureInstance instance)
    public List<Thing> GetConstructedPrefabs()
}

BuildStructure is the prefab the kit places. QuantityUsed is how many of the stack the kit consumes per placed structure (default 1).

OnUsePrimary -> Construct

public override void OnUsePrimary(Vector3 targetLocation, Quaternion targetRotation, ulong steamId, bool authoringMode)
{
    base.OnUsePrimary(targetLocation, targetRotation, steamId, authoringMode);
    Construct(targetLocation.ToGridPosition(), targetRotation, authoringMode, steamId);
}

public virtual void Construct(Grid3 localPosition, Quaternion targetRotation, bool authoringMode, ulong steamId)
{
    if (authoringMode || OnUseItem(QuantityUsed, null))
    {
        CreateStructureInstance createStructureInstance = new CreateStructureInstance(BuildStructure, localPosition, targetRotation, steamId);
        if (PaintableMaterial != null && CustomColor.Normal != null)
        {
            createStructureInstance.CustomColor = CustomColor.Index;
        }
        SpawnConstruct(createStructureInstance);
    }
}

The Quaternion parameter targetRotation flows through unchanged. authoringMode == true bypasses the OnUseItem(...) quantity-consumption check but does NOT bypass any other gate; it is purely a creative-mode item-cost waiver.

SpawnConstruct: simulation vs client routing

public static Structure SpawnConstruct(CreateStructureInstance instance)
{
    if (GameManager.RunSimulation)
    {
        Structure structure = Thing.Create<Structure>(instance.Prefab, instance.WorldPosition, instance.WorldRotation, 0L);
        structure.SetStructureData(instance.LocalRotation, instance.OwnerClientId, instance.LocalGrid, instance.CustomColor);
        return structure;
    }
    if (NetworkManager.IsClient)
    {
        new ConstructionCreationMessage(instance).SendToServer();
    }
    return null;
}

Two execution branches based on simulation role:

• GameManager.RunSimulation == true (single-player or multiplayer host): create the structure directly via Thing.Create<Structure>(prefab, worldPos, worldRot) and call SetStructureData(localRot, ...). The full Quaternion lands on the new GameObject's transform AND is mirrored into Structure.Direction (see GameSystems/PlacementOrientation.md).
• RunSimulation == false && NetworkManager.IsClient == true (multiplayer remote client): wrap the placement intent in a ConstructionCreationMessage and send to server. The server runs the same Thing.Create + SetStructureData path inside the message's Process(hostId) handler.

Either branch preserves the Quaternion losslessly; the wire format uses full WriteQuaternion (16 bytes) per Protocols/ConstructionCreationMessage.md.

Authoring mode

authoringMode is enabled when the player's active hand holds an AuthoringTool (creative-mode wrench). Source: InventoryManager.cs:422 public static bool IsAuthoringMode => Instance.ActiveHand.Slot.Occupant is AuthoringTool;. The flag travels into Construct(... authoringMode ...) and only affects the OnUseItem quantity-consumption call. It does NOT bypass AllowedRotations, CanConstruct, or any other gate. A player in authoring mode still cannot place a AllowedRotations.Floor device on a wall via vanilla input; the cursor's UpdatePlacement snaps the orientation to floor before OnUsePrimary fires.

Verification history

• 2026-04-25: page created from a six-agent decompile pass on the placement pipeline. Source content lifted verbatim from /tmp/decompile_check/Assets/Scripts/Objects/Constructor.cs. No conflicts.

Open questions

None.