How to spread out keyframes parabolically

I would like to create an animation in which something blows up, starting at a normal speed, slows down to a stop, and then reforms. I know I can manually spread out the keyframes in the dope sheet editor (by spreading the keyframes farther and farther apart and then pasting a copy in reverse), but is there a way to do this automatically?

Example of distances between keyframes: 1,1,1,1,2,4,8,16,32 || 32,16,8,4,2,1,1,1,1 Where || is where the new keyframes end and I paste a copy in reverse order.

Doing it manually works when the speed change happens over a few frames, but if I want the process to extend over 60-120 frames, the process becomes both harder to correctly guess the distance, and it takes substantially more time. Is there something such as a way to edit keyframe distance in the NLA editor?

Any help is greatly appreciated. Please comment if anything is unclear.

• By spreading them parabolically, do you mean than the distance between the key frames is goverened by a quadratic equation?
– user7952
Commented Nov 18, 2014 at 1:51
• why not use the graph editor? wiki.blender.org/index.php/Doc:2.6/Manual/Animation/Editors/…
– user1853
Commented Nov 18, 2014 at 2:03
• @SixthOfFour essentially, yes. So ie. Distances: 1,1,1,1,2,4,8,16,32 || 32,16,8,4,2,1,1,1,1 Where || is where the new keyframes end and I paste a copy in reverse order. I have updated the post. Commented Nov 18, 2014 at 2:13
• @cegaton I'm afraid that only deals with interpoliating keyframes; not the distance between them. Commented Nov 18, 2014 at 2:16
• You can use modifiers to create the cycle wiki.blender.org/index.php/Doc:2.6/Manual/Animation/Editors/…
– user1853
Commented Nov 18, 2014 at 2:21