A parameter is a setting or value that you can change. Many objects in 3ds Max have parameters that you can change to alter the size or shape of the object. This type of object can be described as parametric.
A tube is one example of a parametric object. Varying its parameters creates varying geometry.
Unlike physical building blocks, which have a fixed shape and size, the geometric primitives (box, sphere, torus, and so on) are parametric; you can change their dimensions, segment settings, and other features after you create them. Parametric objects respond to changes in their parameters by dynamically updating their properties.
Changing a parameter can dramatically alter the structure and appearance of an object. For example, you can turn a cylinder into a prism by reducing the number of sides and turning the Smooth option off. Alternately, you can turn a cone into a four-sided pyramid using the same technique.
Objects that you merge from other scenes or from Autodesk VIZ allow you to access parametric values. Objects in drawings that you link from Autodesk Architectural Desktop should be edited in Architectural Desktop, then relinked to 3ds Max with the File Link Manager.
You can animate almost all creation parameters for geometric primitives, and interactively change their settings during animation playback.