ZTL file is a proprietary file format used by ZBrush, a popular digital sculpting and painting software developed by Pixologic. It is the native file format for saving and organizing 3D models within the ZBrush environment. ZTL files contain all the sculpting, painting, and other design data, making them essential for preserving the 3D artwork created in ZBrush. The ZTL format allows artists to save their work in progress and resume their projects at a later time, preserving all the intricate details and sculpting information. In addition to storing the 3D geometry of the model, ZTL files also retain information about the layers, subdivisions, and various sculpting and painting tools used during the creation process. This makes it a versatile and comprehensive file format for ZBrush users. When working with ZTL files, it's important to note that they are tailored specifically for ZBrush and may not be compatible with other 3D software applications. However, ZBrush does provide options for exporting models in more widely compatible formats such as OBJ or FBX for use in other 3D programs. Overall, the ZTL file format plays a crucial role in the ZBrush workflow, allowing artists to save, organize, and preserve their 3D creations with all the intricate details intact.