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.
I made both a slow-down addon and a reverse addon. A combination of those two may be helpful?

How can I slow down or animate time?

How to reverse an animation?

EDIT

This is designed to help you with the result you are looking for, which is not necessarily parabolic.