About Mill Window
The simplest way to define geometry for a Volume or a 3-Axis Conventional Surface milling NC sequence is by using a Mill Window, that is, by projecting the silhouette of the reference part on the Mill Window start plane, by sketching or by selecting a closed contour. All surfaces visible within the contour are milled.
To create a Mill Window, click Manufacturing > Mill Window.
Creo NC activates the Mill Window definition tab. Creo NC also assigns a default name to the Mill Window. You can later modify this name.