Preferences - Show Layers Tab
Display layers while moving layer handle: Check this option to view layers in real time while moving the layer handle up or down in the front view of the main window in either 2D or 3D view.
Display layers during collision detection: Check this option to display layers while running collision detection.
Delay between layers in collision detection: Input a value for displaying layers while running collision detection. A higher number will display at a slower rate than a lower number.
Display current layer number and height in 3D view: Check this option to display the number and height of a selected layer while in 3D view.