* No single render time: The film's visual effects were spread across multiple studios and involved countless individual render tasks. These tasks varied in complexity, meaning some scenes took hours to render, while others might have taken days.
* Technological advancements: Render times have dramatically decreased over the years. Avatar was released in 2009, and rendering technology has improved significantly since then. What might have taken days back then could now be done in hours.
* Focus on visual quality: While speed is important, the primary focus was on achieving the desired level of visual quality. The rendering process was likely iterated multiple times to fine-tune the effects and achieve the director's vision.
However, we can get some clues:
* Early reports: Some sources mentioned render times exceeding 48 hours per frame for some scenes.
* Industry standard: At the time, it was not uncommon for high-end VFX shots to take 12-24 hours per frame.
It's safe to say that the total rendering time for Avatar was significant, but it's impossible to pinpoint an exact number.