Connection¶

A Connection is one OpenEnd of a SmallGrid (cable, pipe, device, chute, rail). The list of OpenEnds on each SmallGrid is what ConnectedCables / ConnectedDevices / Connected iterate over to discover adjacency.

Fully qualified type and shape¶

Assets.Scripts.Objects.Pipes.Connection (decompile line 293240). It is a plain [Serializable] POCO, NOT a MonoBehaviour and NOT a UnityEngine.Object. So it has no name property; the Connection object has no Unity identity of its own. Patches that want a human-readable identifier should use connection.Transform.gameObject.name (which is the name of the child GameObject the Connection was attached to in the prefab, e.g. OpenEnd1, Input, Output).

Verbatim shape (line 293239 onward):

[Serializable]
public class Connection
{
    public NetworkType ConnectionType = NetworkType.Pipe;
    public Transform Transform;
    public Collider Collider;
    public ConnectionRole ConnectionRole;
    [ReadOnly] public Renderer HelperRenderer;
    public SmallGrid Parent;
    public Grid3 LocalGrid;
    public Grid3 FacingGrid;
    private bool _isInitialized;
    private bool _isValid;
    public Vector3 TransformUp { get; set; }
    public bool IsValid { get { ... } }
    ...
}

Key fields for adjacency lookups:

ConnectionType is a NetworkType enum bitmask (Pipe / Power / Data / Chute / Rail). Used by SmallGrid.IsConnected(Connection) to gate cross-network mismatches.
Transform is the Unity transform of the GameObject the Connection was prefab-bound to. Transform.position is what SmallGrid.ConnectedCables() and friends pass to GridController.WorldToLocalGrid to find the adjacent SmallCell.
LocalGrid and FacingGrid are precomputed Grid3 coordinates: LocalGrid is the cell the Connection sits in (the one the parent SmallGrid's body occupies on that side), FacingGrid is the cell the Connection points AT (the cell beyond the body). IsConnected asserts that the other side's LocalGrid equals this side's FacingGrid.
Parent is the SmallGrid (Cable, Device, Pipe, etc.) that owns this Connection.
ConnectionRole is the directional/role tag (Input, Output, Output2, Waste, ...).

Data-port discovery and the PowerAndData connector¶

NetworkType is [Flags] (decompile L293197): None=0, Pipe=1, Power=2, Data=4, Chute=8, Elevator=0x10, PipeLiquid=0x20, LandingPad=0x40, LaunchPad=0x80, RoboticArmRail=0x100, PowerAndData=6 (= Power | Data), All=int.MaxValue. A device's "data port" is not a dedicated field; it is discovered from the OpenEnds list:

Device.DataConnection (decompile L349649) returns OpenEnds.Find(c => c.ConnectionType == NetworkType.Data || c.ConnectionType == NetworkType.PowerAndData) -- the first connector carrying data, whether a Data-only connector or a combined PowerAndData connector.
SmallGrid.HasDataConnection (a [ReadOnly] bool, L293498) is set in SmallGrid.Awake (L293563) by scanning OpenEnds for those same two types.
SmallGrid.GetConnection(NetworkType type, ConnectionRole role, out Connection) (L293576) fetches one connector by type + role.

Consequences for "how many connectors does a device have":

Data riding on a power connector = an OpenEnds entry typed PowerAndData (=6); DataConnection returns that same physical connector. Typical 2-connector power device (power-in + power-out, one of them PowerAndData).
A dedicated data port = a separate OpenEnds entry typed Data (=4) alongside the Power connectors. This is the 3-connector shape on rocket-internal device prefabs (see Transformer, Battery, RocketPowerUmbilical).

The number of OpenEnds entries and each entry's ConnectionType / ConnectionRole are serialized prefab asset data (the only ConnectionType = assignment in the decompile is the field default = NetworkType.Pipe). The decompile gives the model; the per-prefab layout requires a live read (InspectorPlus OpenEnds dump, or a Prefab.AllPrefabs ScenarioRunner dump).

Verification history¶

2026-06-18: added "Data-port discovery and the PowerAndData connector" section (NetworkType.PowerAndData=6 at L293197, Device.DataConnection L349649, SmallGrid.HasDataConnection L293498 set in Awake L293563, GetConnection L293576). Additive, sourced from a PowerGridPlus rocket-device investigation; no conflict with existing content.
2026-05-15: page created. Sourced from decompile line 293240 (class declaration) and the Connection field listing immediately after. Created while writing a Bug 2 diagnostic Harmony patch that needed to log per-OpenEnd identity; the patch initially used connection.name which fails to compile because Connection is a serializable POCO without a Unity name.

Open questions¶

None at creation.