This is insanely impressive. For fingering, in the right hand I typically put my pinky on the highest note for a phrase, it feels more comfortable and you can accent it more than the middle fingers. In the left hand I typically put the bass note in the pinky as well. The middle fingers aren't as dextrous so I use them less, though a concert pianist could probably use your fingering. Overall technique wise, human hands cup their hands more, the palm is arched where the robot's is flat. But who says it needs to model humans exactly. I can't believe this is working in three.js! Amazing work!