What is a IO file? An IO file is a LEGO Model created by LEGO BrickLink Studio, an app for building and sharing custom LEGO designs. It stores a LEGO design, which includes parts that make up a model (bricks, plates, bars, tiles, minifigures, etc.), and instructions for building the design.

More Information IO file open in LEGO BrickLink Studio 2 Studio is a helpful tool for LEGO enthusiasts looking to build their digital designs, render them, and create detailed instructions for piecing them together. The IO file is the primary file type associated with BrickLink Studio. When you create a LEGO model and save it by selecting File → Save or Save As...... , Studio creates an IO file to store the model contents. After saving a model, you can close it in Studio, then re-open it to continue modifying it. After you finish building a model and creating instructions with Studio, you can export it to another model format by selecting File → Export As . Or, you can upload it to the BrickLink market (via the BrickLink option) to share with other users, who can then order it as a custom set.