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Interesting but lacking some information. First up, of course, most people are familiar with rotating the camera rather than a single object. This is how most 3d viewers work, even if the orbit point is locked to the center of an object (e.g. in a 3d product display). So it's important to specific which we're talking about in an introductory article on 3d rotation methods. But, ok. We're talking about schemes to rotate a single object rather than the camera. The turntable controls they talk about are a special case of gimbal controls where we lock rotation to one or two axes. But in my personal experience, when it's two or three axes people still call it gimbal controls whereas turntable controls is rotation in a single axis (as if on a turntable, hence the name). But then again, 3d terminology is so mixed up across different fields that maybe some people have only heard the two axes version called a turntable. Not a big deal, but why no mention at all of gimbal controls? Then, trackballs. In my experience, when it's limited to a single hemisphere of rotation, these are called arcball controls. Trackballs are supposed to emulate a trackball mouse which don't have this limitation. And finally, no mention at all of the dreaded gimbal lock (where two of axes end up overlaid on each other and the controls loses a degree of freedom), which is a major reason for choosing one type over another. Overall, not an amazing article. I checked it again to see if I missed anything and realized it's a blog post for some app - so, basically an ad - which probably explains the lack of effort. |