Spline is a web-based, real-time, collaborative 3D design tool that allows users to create interactive web experiences. It offers a range of features, including 3D modeling, animation, material layers, and physics simulations. The tool is designed to be user-friendly and is trusted by teams for its ease of use and flexibility. Spline allows for real-time collaboration, enabling teams to work together on 3D designs and set individual permissions. It also provides the ability to export designs as various file types, integrates with React projects, and offers a template library for ready-to-use design elements. Users can also integrate their 3D designs into web projects using simple embed codes. Overall, Spline is a comprehensive 3D design tool for creating and collaborating on interactive web experiences.