Maya keeps track of the options, attribute settings, and transformations made to an object via its construction history. Construction history is useful when you’re working on a surface and want to edit an attribute from an earlier stage of the model’s development.
The simplest way to access the construction history for an object is via its various input nodes in the Channel Box or via the Attribute Editor. Selecting an input node displays the attributes associated with that particular modification to the object. You then edit the attributes on that node as required and the surface updates.
For example, the input nodes for the helmet mesh include: polyCreateFace, polyCube, polyExtrudeFace, polySmoothFace, polyMoveVertex, polyUnite, and so on. You can associate the steps in creating the helmet mesh with nodes that are related to a particular stage of its construction history.
As you near the completion of a model, these construction history nodes are not required. If your production work entails having another person texture or animate the model, you’ll want to delete these history nodes from the objects in your scene altogether so another user doesn’t accidentally change your work.
Deleting the construction history is usually done only when a model is completed to a particular milestone stage and the next major phase of production with it needs to occur. For example, skinning, animating, texturing, and so on.