Automatic Center-of-Rotation for Interaction
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
The center of rotation for a camera is very important for interacting with data/geometry in paraview. Setting it to the center of the data bounds is good enough for interaction with the camera placed far from the model such that it fits on screen. However when zooming in to a small portion of the geometry then rotation causes the user to get lost quickly. Additionally when the center of rotation is behind the camera the translation is backwards, and when the COR is at the camera the translation is very slow. Instead the center of rotation must be set to some point on the small portion of geometry in view. In PV 2.x this could be done by a pick operation, but even that was prohibitive.
I propose a feature to enable an (optional) interaction mode that automatically selects a new center of rotation after any translation/zoom of the camera. The selected center should cause rotation to be close to what the human viewing the window expects. Obviously this is a bit subjective but any policy is probably better than the current behavior. Perhaps it could be something as simple as a weighted average of the z-buffer with higher weight given to the samples at the center of the window.