An object's structure elements are the properties of the object relative to its parent.

The structure elements are as follows.

**Parent**is the parent in the object structure, and has the symbol**P**.The parent in the object structure is never explicitely editable, and is determined by the structure of the system.

**Lineage**is the lineage in the object structure, and has the symbol**L**.The lineage in the object structure is never explicitely editable, and is determined by the structure of the system.

**Distance**is the distance from the parent, and has the symbol**r**.The distance from the parent must be a number greater than zero.

**Speed**is the orbital speed, and has the symbol**v**. This describes the speed of the object relative to its parent.The orbital speed must be a number greater than or equal to zero.

**Orbital Period**is the period of the orbit, and has the symbol**T**. This describes the time that the object takes to complete one orbit.If the orbit is closed (a circle or an ellipse), the period of the orbit must be a number greater than zero. If the orbit is open (a parabola or a hyperbola), the period of the orbit must be infinite.

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