Enclosed volumes with stereolithography 3D printers
The bubble will contain air, but this will vary by printer. Most resin printers lift the printed part out of the bath slightly after each layer. Some printers, however, don't lift the piece completely out of the bath. This will cause the resin to become entrapped. Once those entrapped pockets of resin are exposed to light, they will also undergo photopolymerization. It may be possible however to program those printers to lift the part completely out of the resin for each layer.