The 3D modeler can be used as an advanced option for your 3D smile desing. 

When should this feature be used?

To customize further- Use the 3D modeler to customize further or adapt your 3D smile design. This feature will be used after you have exported your initial desing for printing. Let's say, for example, that you need to alter or change details after you have printed your design. Instead of re-opening the desing and starting from the beginning, you can open the 3D modeler, re-import the design into the app and work with sculpt tool to adjust your desing further.