This form is displayed when you press the Animation Properties button 
within the 3D view control tools. It is used to configure the 3D Animation properties.
3D Properties - Animation
Length
Total Frames
Enter the number of frames required in the animation.
Duration
Frames/sec
This value determines the speed at which the animation is played. As you change this value the Duration will be automatically updated.
Duration
This value determines how long the animation will play for. As you change this value the Frames/sec will be automatically updated.
Advanced
Animation frame steps
This value specifies the number of frames to step through when choosing Next Frame or Previous Frame when using the 3D Tools > Animate or the Animation Editor.
Auto Apply
If this option is switched on, then any changes made to the form are automatically applied immediately.