NBA 2K15 will not be available until fall this year, but we already have a sneak peak at some of the behind the scenes. It's a short clip from the motion capture process for dunk animations. 2K Sports posted this recently on their official Instagram account with a description that says “The 2K team is grinding away! Check out some dunks being recorded for #NBA2K15.”
The video shows some players wearing mocap suit and performing dunks including between the legs, tomahawk slam, and elbow dunk ala Vince Carter. These recordings are then given to the animators; the amazing dunks are kept to create the seamless motion that you see in the game. You can watch the embedded video below.
Here's another behind the scene video uploaded by Gary "G" Smith. He's one of the guys who perform sick poster dunks for the game.
NBA 2K15 is expected to arrive by the end of the year. There's no official announcement yet on which platforms the game will be released, but the expectation is that it'll probably land on Xbox 360, PS3, and PC first and then head to next-gen consoles (PlayStation 4 and Xbox One).