After you create a component family, define the family origin and pin (lock) it in place. Later, when you create an element with the finished family, the family origin specifies the element insertion point.
The intersection of 2 reference planes in a view defines the origin of a family. You can control which reference planes define the origin by selecting them and changing their properties. Many family templates create families with predefined origins, but you may need to set the origin of some families. For example, an accessible toilet family that creates toilet elements must always be placed a certain distance from an adjacent wall to meet code. Therefore, the family origin would need to be located at the specified distance from the wall.
To define the family origin in a new family
If Defines Origin is selected for 2 intersecting reference planes, the origin is defined for the family, and you can skip the remaining steps.
To define the family origin in an existing family
The intersection of the reference planes now defines the origin/insertion point of the family. By pinning the planes, you ensure that you do not accidentally move them, which would change the family insertion point.