I'm working with the viewer API and I've built a few buttons with preset camera angles next to my embed. This gives my users the option to freely navigate the model but also pick from a front/side/closeup view. I also switched the autospin option in my embed on. But that was a bad idea.
I always assumed autospin rotates the camera, but it doesn't. The model is rotated (if I'd paid attention I would have known...). This makes my buttons with my preset camera angles obsolete since I can't put the model back at it's original rotation when picking a camera angle. In order to have the autospin AND preset camera angles I'd need to be able to reset the model rotation through the API.
As an alternative the viewer could have an extra parameter to automatically spin the camera "cameraspin". Autospin and cameraspin would need to be mutually exclusive of course.
In addition to that, another viewer option to automatically spin the lights would be awesome: "lightspin". It really helps to sell a model when there's a bit of 3D movement. However, sometimes you don't want to move the model because of a specific camera angle. Moving the lights is a great alternative. I know you can do this by hand, but having an automatic lightspin is really neat.