Hi @Anonymous,
The circular track that would allow for the camera to run around is a good addition, however if the subject of interest moves even the slightest bit, it would affect the reconstruction of the images. Having multiple cameras with a fixed rig would be a better solution for your purpose.
As for the angle where the photo to be taken, do ensure that all angles are taken, not just from the top down, but also bottom up to ensure areas under the chin and the undersides are captured as well. There are no hard rule on how many photos that have to be taken, however, there should be a good overlap (of at least 60% to 80% overlap) of the photos when taken to ensure a good reconstruction. As for the focal length, make sure that all photos are crisps without any depth of field in the foreground or background, I would a say an aperture of around F11 should suffice. Diffused lighting has to be constant for all the photos as well, so that no harsh shadow will be cast. Dimensions of each of the frames will not affect the reconstruction, as ultimately the resolution of the photos are what that is taken into account for the reconstruction.
For more information on good practices for photogrammetry, you can refer to this: https://knowledge.autodesk.com/support/recap/learn-explore/caas/sfdcarticles/sfdcarticles/Taking-the-right-pictures-for-use-in-Autodesk-ReCap-Photo-video.html
Do let me know if you got any other queries!
Cheers,
Gerald Chin
Senior User Experience Designer,
Autodesk Vault