Network Visibility & Culling

Network Visibility controls whether a networked object should be visible for a specific player (Connection). Visibility determines whether the object receives ongoing network updates — such as Sync Vars and Transform updates — for that client.

By default, all networked objects always transmit to all Connections, unless you explicitly disable this behaviour.

Always Transmit

Every networked object has flag called Always Transmit.

• Default: AlwaysTransmit = true
• When true, the object never gets culled and is visible to every player.

This is the simple default for beginners, but for larger or more complex games, disabling Always Transmit can enable performance benefits by culling objects that the player should not receive updates for.

INetworkVisible Interface

You can take control of visibility by attaching a Component to the root GameObject of a networked object that implements Component.INetworkVisible.

Only the owner of a networked object decides visibility for each connection.

public class MyVisibilityComponent : Component, INetworkVisible
{
    public bool IsVisibleToConnection( Connection connection, in BBox worldBounds )
    {
        // Your visibility logic here…
        return true;
    }
}

IsVisibleToConnection Parameters

Return true if the object should be visible to that connection; false if it should be culled.

To enable this behaviour, disable AlwaysTransmit on the root network object.

Hammer PVS Integration

If no component implementing INetworkVisible exists on the root GameObject and the map is a Hammer map with VIS compiled:

• The engine automatically falls back to PVS (Potentially Visible Set).
• Visibility is determined using Hammer's visibility data.

This is an ideal default for static world objects on Hammer maps.

What Happens When an Object Is Culled?

When the owner decides an object is not visible to a connection:

The following stop being sent:

• Sync Var updates
• Transform updates

The following still occur:

• The object still spawns for the client.
• The object becomes Disabled locally for that client while hidden.
• RPCs are still delivered.

Invisible objects remain known to the client, just not updated.