When do we need to hollow the model

1. Material Savings: Hollowing a model reduces the amount of material used, which can be especially important when using expensive materials. This reduction also lowers the overall cost of the print.
   
2. Weight Reduction: For larger prints, making the model hollow decreases the weight, which can be important for practical applications where the final object needs to be lightweight.
   
3. Structural Requirements: In some cases, the design's structural integrity does not require it to be solid. For example, decorative objects or parts that do not bear significant loads can be hollowed without compromising their function.
   
4. Resin Printing Considerations: Hollowing is often necessary to prevent the creation of a large, solid mass of resin, which can be heavy and difficult to cure properly. Hollow models also allow for better light penetration during the curing process.
   

When hollowing a model, it's crucial to add drainage holes. These holes allow uncured resin to escape and prevent the creation of vacuum pockets or pressure build-up that could cause print failures or defects.

How to hollow the models

1. Hollowing models:
   

   In Edit interface, select the model, then click Hollow feature, the model will be hollowed.
   

   

   Note: For certain applications, such as thermoforming clear aligner, the wall thickness of hollow models should be greater than 3mm, and the hole thickness should be greater than the wall thickness.
   

   
   

   
   

1. Digging holes.
   
   In Edit interface, select the model and click Hole feature, then select position of holes on the bottom of the model, click Apply.