We have changed the User-Defined Split feature in e3. Now this feature is incorporated into the Carving Stamp feature.
1) Click on the Carving Stamp button to open the Carving Stamp dialog box
2) In the Digitize tab, click on the “Start Digitizing” button
3) Digitize the “User-Defined Split” lines on an object
4) Click on the “Stamp” button, which is found below the “Start Digitizing” button in the Digitize tab in the Carving Stamp dialog box
Note: the User-Defined Split is applied to the object. There is an improvement to previous functionality as you can now reshape the User-Defined Split lines in the object reshape mode.