Establishing Parent-Child Relationships between Objects in Blender
Creating parent-child relationships between objects, or parenting in Blenderese, organizes the objects hierarchically. An object can have any number of children, but no object can have more than a single parent:
To make an object a parent, first select the objects you want to be children.
They don’t have to be of the same type.
Make your last selection (the active object) the object that you want to become the parent.
Press Ctrl+P→Object or click Object→Parent→Object in the 3D View’s header menu.
After you confirm the operation by left-clicking or pressing Enter, Blender adds a dotted line from the origin of each child object to the origin of the parent. Now when you select just the parent object and perform a transform operation on it, it affects each of its children. However, if you select a child object and transform it, none of the other children or the parent object are influenced.
A good mnemonic device for remembering the correct order for selecting objects when you want to create a parent-child relationship is to think of the order people get off of a boat when they’re abandoning ship: “Children first!”
Parenting is a great way to organize a set of objects that have a clear hierarchy. For example, say that you’ve modeled a dinner table and the chairs to go around it. Now you want to place that table and chairs in a room, but the room is scaled much smaller than the table and chairs. Rather than select, scale, grab, and move each object into place, you can parent each of the chairs to the table. Then you can just select and transform the table. When you do so, all the chairs transform right along with it, as if they were a single object!
Woohoo! The figure illustrates this example.
To clear a parent relationship, the process is only a click and a hotkey:
Select the child object that you want to remove from the hierarchy.
Press Alt+P or click Object→ Parent→Clear Parent in the 3D View’s header to clear the parent relationship.
If you use the hotkey, you see a pop-up menu with three options:
Clear Parent: This option removes the parent-child relationship between your selected object and its parent. If the parent object was transformed after the parenting took place, the cleared child jumps back to the position, scale, and rotation that it was in before it was parented.
Clear and Keep Transformation (Clear Track): This option behaves the same as Clear Parent, except any transformations that were made while the selected object was a child are applied. This means that the cleared child does not snap back to its original pre-parented state.
Clear Parent Inverse: This option is a bit tricky to understand. It actually does not remove the link between the selected child object and its parent. Instead, it basically clears the parent’s transformation from the child. Clear Parent Inverse is handy for situations where you’ve transformed an object before parenting it, and you want it to relate to the parent as if it had not been transformed prior to parenting. To be honest, I don’t use this option very often, but it’s certainly good to have around when you need it.
Another quick way of parenting within Blender is from the Outliner. Within the Outliner, you can left-click the icon of any object and drag it over the name of another object in the Outliner (essentially dropping it in like copying a file into a folder on your computer’s file browser). That action automatically creates a parent-child relationship between the two objects. On complex scenes, this is an extremely handy trick.