Generally speaking, grabbing the center of the translation manipulator should only move the object along a plane normal to the view perspective. If this view is locked to an axis and orthogonal, the third axis should be eliminated from the translation altogether.
Currently, if i click on the X-axis of the perspective cube widget, and grab the center of the translation manipulator and drag (which should now only move the object on its Z and Y axes), there is still X-axis deviation, seemingly random as well. Coming from other 3d packages (most notably Maya), this is a crazy behavior.
What this means is that if i want to quickly look at a side view and move an object only on its Y and Z axes, i’m practically boned.
Is this a bug? If not, why does this behavior exist? If i’m looking directly at an axis manipulator from an orthogonal point of view, why in gods name am i allowed to grab it? If i’m looking down the X-axis, its manipulator should be hidden.
Sidenote, i’d really like Unity to copy Maya’s “exclude axis” behavior (hold control and click+drag an axis to manipulate only the two others; seems weird but a total timesaver). In any case we need some ability to move objects on two axes simultaneously.