Continuous liquid interface production (CLIP) is a layerless AM. In inverse stereolithography, where a part is made upside down, a film is attached on the inside of an exposure window so the solidified layer can be detached from the window before resin flows for the next layer to be formed. In CLIP, an oxygen-permeable window instead of a film is used. Oxygen gas entering through the window reacts with free radicals and neutralizes them so that they will not be free for further polymerization on or near the window. In the absence of polymerization, there will not be any solidified material on the window required to be detached from. This makes the process free from the following problems: detachment, repositioning the substrate after detachment, breakage of features during detachment, and not making a large area because of the problem of detachment. Utilization of oxygen molecules to inhibit photopolymerization makes the process different from stereolithography, where inhibition by such a method is not used.