The Modifier Stack

The modifier stack encloses two intertwining concepts: the modifier and the stack. A modifier, like the parametric object, is an object (a function with input values that produce an output). The inputs, which come from different sources, are of two types:

• The state of the object being passed to the modifier
• The values the user chooses to apply to the modifier

These ideas are quite difficult to grasp. Here are some examples to help you understand these different types of inputs.