Spline is a web-based 3D design tool that allows real-time collaboration among users. With features like interactive 3D experiences, game controls, 3D sculpting, physics simulations, and more, Spline provides a solid set of tools for expressing creativity in 3D. Users can work on projects in real-time with team members, set individual permissions, and create parametric objects and animations effortlessly. The tool also offers the ability to organize designs into teams, projects, and folders, and supports exports in various formats like images, videos, and 3D files. Additionally, Spline enables users to integrate their designs into web projects using simple embed codes or snippets, making it a versatile solution for 3D design collaboration.