An object’s creation parameters are settings, typically available on its Parameters rollout, that you make when you first add the object to the scene. You can later adjust these settings by accessing the object at the bottom of its modifier stack. For example, a Box primitive’s creation parameters are its size and number of segments in each of the three dimensions. You can usually adjust an object’s size without scaling it by changing its creation parameters.
If you collapse an object, its creation parameters are lost, and can no longer be adjusted.