Modify > Replace Objects

Replaces one or more objects in the scene with a specified source object. Select the objects you want to replace as well as the object you want to use as the source object. The source object must be the last object in the selection.

Attributes to copy

Attributes copied are copied from the original object being replaced to the new object.

Rotate: Copies the Rotate attributes from the original object being replaced to the new object. The default setting is on.
Scale: Copies the Scale attributes from the original object being replaced to the new object. The default setting is on.

Type of Copy

Specifies how the new objects get created. You can select Copy, Instance, or Reference.

Copy: The new objects are duplicates of the source object with their own separate shape nodes. This is the default setting.
Instance: The new objects are instances of the specified source object and share one shape node. When Keep last selected object is on, the new objects are instances of the source object and share its shape node.
Reference: Use this option only if the source object is a reference. New objects will also be references. Otherwise, use the Copy or Instance options to replace objects with the referenced source object.

Note
If you attempt to replace two or more objects with a reference you will not be able to Undo.
Keep last selected object: The source object is kept by default. Turn off Keep last selected object if you want the source object to be automatically deleted.