VR Mocap Studio allows one to impose data of finger motion received from the Leap Motion controller on already existing animations. To do that, you need Leap Motion controller with desktop setup. More info on the official site.
Fingers must be initialized in parameters of skeletal mesh in the Fingers tab.
Select skeletal mesh in the drop-down list and switch to the View Animations tab to get started.
Choose animation for which you want to record finger motion from the list and press 
(play) button. Then pause the animation playing using 
(pause) button.
You can enable the preview mode for fingers by pressing 
button in the bottom left corner. Fingers will be animated both in pause mode and while playing animation.
To begin recording, turn off the preview mode and rewind the animation in the pause mode to the moment from which you want to start the recording.
Press 
button to start the recording. The icon will be changed to 
"stop recording" icon. The starting time of the overwritten interval will be are marked with a red line.
The recording of finger motion will stop after pressing the same button again. Also, the recording will stop automatically after it reaches the end of the animation.
All the changes are saved automatically and they cannot be undone. To preserve the initial animation, duplicate it before you begin recording of finger.