The MolecularWeb Universe: Web-Based, Immersive, Multiuser Molecular Graphics and Modeling.

For decades, software for molecular visualization has been a cornerstone of research and education in the chemical and structural sciences. It is unfortunate, however, that consumer devices enable only flat 2D inputs and outputs, which brings two problems. First, traditional 2D screen-mouse interfaces struggle to convey the inherently three-dimensional nature of molecules and their interactions. Second, probably worse, the thoughtful manipulation of molecular structures in three dimensions is very hard to achieve with 2D peripherals. Immersive technologies under the umbrella of eXtended Reality (XR, including augmented and virtual reality, AR and VR) promise to revolutionize how we learn, teach, and conduct research in the chemical and structural sciences, by assisting both how we see and how we manipulate molecules in 3D. This chapter chronicles the development of the "MolecularWeb" ecosystem, a suite of web-based tools designed to make immersive molecular visualization and interactive modeling and simulations widely accessible to a broad audience. Centralized at https://molecularweb.org , these tools have found wide applicability in education and science communication, promising to directly assist research as well. We describe first MolecularWeb, which delivers activities and tools for education in pass-through and mirror-like AR using regular devices like phones, tablets, and computers. We then cover MolecularWebXR, a platform for multiuser immersion using WebXR-enabled headsets-yet remaining accessible with simpler devices-that brings content about chemistry, materials sciences, and structural biology in formats engaging for educational and science outreach activities, also serving for immersive scientific discussions. A short visit to PDB2AR will show how users can create tailored content for MolecularWebXR and also stand-alone AR and VR experiences. We finally delve into our HandMol prototypes, which allow for immersive visualization of molecular systems and their modeling with bare hands in immersive 3D by multiple concurrent users assisted by on-the-fly molecular mechanics calculations, seamless file exchange, a language model module that interprets users' inputs without them having to learn any menus or scripting, alternative immersive access with consumer devices, and more. With the various tools presented, we offer a glimpse into the present and near future of accessible, interactive, and intuitive molecular science on the web.