What was the main advanced technology used in the film "Avatar"?

The main advanced technology used in the film "Avatar" was 3D technology and motion capture, which played a crucial role in bringing the film’s innovative visual effects to life. James Cameron, the director, utilized state-of-the-art motion capture techniques that allowed the performers to convey their emotions and movements in real-time. This technology captured intricate details of the actors' performances and translated them into the animated characters, resulting in a highly immersive experience.

Furthermore, the use of 3D technology allowed audiences to view the film in a way that heightens the sense of depth and space, creating a more engaging visual experience. The careful integration of these technologies was a significant factor in the film's success, setting new standards in the industry and showcasing the potential of blending live-action with computer-generated imagery (CGI).

In contrast, the other options do not represent the primary technological innovations that "Avatar" is known for. 2D animation and stop motion animation are traditional techniques that were not a focus in this film, while green screen technology, although used in many films, did not embody the groundbreaking advancements demonstrated in "Avatar."