I am developing an 3D editor. I think showing 3 rings around the object to manipulate should be most intuitive because you have a feeling of "handling" it. Hovering one of the rings highligts it to indicate that you rotate the object around it by mouse down.
The arrows move the object in space and should not rotate with the object! I think this is needed because rotating these arrows with the object implies that the user (definitely) looses his orientation in 3D space! Many programs do it but it feels very akward!
In general I think only rotating around one axis at a time is much more intuitive instead of using x,y mouse coordinates to rotate around two axes at a time. In my opinion it is much more intuitive using grippers as you know it from 2D graphic applications.
But there are different solutions to rotate the object in 3D space.
- you can rotate around fixed object axes (like in the three.js editor)
- you can rotate around the object axes (which implies that you rotate around the already other rotated axes!)
- a) user selects a plane b) user rotates around it's normal
- other solutions?
I think this is a big problem in 3D editing in general. There isn't a standard solution in CAD programs/3D editors.
I want the most intuitive way so that even my mother can use it. I am not searching for the most effective/fastest way to manipulate objects in 3D space.
Update: The three.js Editor does a good job but I am still in research of a more intuitive solution. It is hard to undo rotations. Maybe showing degrees at the rings is a solution.