In the most recent Clone Wars episode, Ashoka and Darth Maul crossed lightsabers in one of the most intense duels in the entire series. A new behind-the-scenes video shows just how much work went into creating the climactic battle on Mandalore.
Stuntman Ray Park was brought on board to capture the physical essence of Darth Maul after playing him back in The Phantom Menace and Solo: A Star Wars Story. While he was dubbed over in the films, it was Park who was performing those flips and twirls in each fight.
This was the first time motion capture was used in the series. It took layers and layers of animation and lighting effects over the motion capture footage to create the final product.
Source: Gamespot Star Wars: The Clone Wars Behind-The-Scenes Of That Darth Maul Lightsaber Duel