Parent-child relationships

Overview

Objects with the CoherenceSync component can be connected to other objects with CoherenceSync components to form a parent-child relationship. For example, an object can be linked to a hand, a hand to an arm, and the arm to a spine.

When an object has a parent in the network hierarchy, its transform (position and orientation) will update in local space, which means its transform is relative to the parent's transform.

A child object will only be visible in a LiveQuery if its parent is within the query's boundaries.

Usage

Creating an Entity hierarchy is very simple. All you need to do is add a GameObject with a CoherenceSynccomponent as a direct child of another GameObject with a CoherenceSynccomponent. You can add and remove parent-child relationships at runtime (even from the editor).

Destruction or disconnection of the parent object will also destroy and remove all children of this object. Those objects' state needs to be treated on the Client side to be reinstantiated on the next connection.

Hierarchies with intermediary transforms

Sometimes, it is not practical to add CoherenceSyncobjects to all the links in the chain. For example, if a weapon is parented to a hand controlled by an Animator, we do not need to synchronize the entire skeleton over the network. In that case, see CoherenceNode.

Level of detail considerations

If the child object is using LODs, it will base its distance calculations on the world position of its parent. For more details, see the Level of detail documentation.