Export atomic models with joints for GLTF animation

[Tom Goddard]

GLTF files can contain "skins" which use "joints" to animate a model, typically a human character with head, arms, hands, legs.... This could be used to make a jointed molecular molecule consisting of rigid domains, for instance, a sars-cov-2 spike with its receptor binding domain able to swing up or down. Such jointed models might be useful in VR or with flat-screen 3D graphics to allow a user to tug on the different domains to understand the major modes of flexibility. The joints would be derived from atomic models representing multiple conformations. How to figure out a good set of joints would be an interesting problem.

Jointed molecular models would be interesting in VR. Whether it is useful to export to GLTF depends on whether there are existing viewers which could be used to explore such models. If we just wanted to allow manipulating a jointed model in ChimeraX there would be no need to export to GLTF. If generic viewers that allow hand interaction with jointed GLTF models exist, the NIH 3D archive might be interested in this type of model.

Phil Cruz mentioned another example of sars-cov-2 virus spikes going from prefusion to postfusion states.