All Files Enabling Constant Z T-HFND-009-008A You can also enable the Constant Z option directly in the Function view for specific functions. How to enable the Constant Z option In the Timeline view, expand the layer on which you want to set the Constant Z feature. Note that you must select the 3D Path option for the layer. Double-click on one of the position functions to open the Function editor. In the Function editor, select the Constant Z button.