What does the autokey button do in 3ds max?

Answer 1

Lets say that you've made a box in the scene. If you move the play head of the time line to another frame and move or rotate the box, then return the play head to the 0 position, you will notice that the box is in the new position still.

Now, do the same again, only this time press the Auto Key button before you move the box. The time line will go red, showing that the Auto Key function is on. Go forward along the time line and move the box or rotate it slightly. If you scrub along the time line now, you will notice that the box now animates from its original position to the new position.

This is how animations are done in 3DS Max. Whatever you select at a different frame while Auto Key is on, it will, like it states, automatically place a key frame on the selected object's parameters that are modified, such as position, rotation and scale. If you turn off Auto Key and decide the box should be somewhere else, you will not have moved the object's animation parameters, only the position, rotation and scale of the object and the animation will conform to the relative new parameters. This means that you can send the object and its entire animation to another position or scale it to fit the scene.