Sometimes interpolate all frames is not convenient and it's better, for example, interpolate in twos.
The new parameter allows to define the number of frame for each step, by default is set to 1 as before.
{F8812621}
This is a request of animators to improve interpolate tools.
Reviewed By: mendio
Maniphest Tasks: T80190
Differential Revision: https://developer.blender.org/D8723
239b0b