Though there’s still no firm start date for the promised Avatar sequels, we’ve recently been privy to a few updates on the multiple follow-ups to the highest grossing film of all time.  Last weekend we learned that the planned Avatar 4 would be a prequel to the first film and would be filmed separately from Avatar 2 and 3, and now Cameron has spoken a bit about the writing process for 2 and 3 as well as the technical challenges that he and his team face.The plan is to shoot both films simultaneously, and when talking about how he’s approaching the dual sequels Cameron mentioned a couple of other follow-ups that were filmed back-to-back as an example of what not to do.  Hit the jump to see what he had to say.Speaking with the LA Times, Cameron said that he’s gearing up to go off to his “top secret writing cave” to finish the scripts for Avatar 2 and 3, but as evidenced by the prolonged development time, it’s no easy undertaking:

“It’s a little bit of a daunting writing task because it’s two scripts and they’ve both gotta be done at the same time. I’m writing it as separate stories that have an overall arc inclusive of the first film. I don’t want to suffer from the Matrix 2 problem, where it just ends, like, what the hell? It’s gotta end. There’s gotta be a sense of conclusion, but also a sense that the journey will continue, and that’s a fine line.”

Many fans were scratching their heads at the end of The Wachowskis’ The Matrix Reloaded, but it looks like Cameron is insistent that Avatar 2 will feel like its own complete story even though it shares an arc with Avatar 3.

It’s no secret that Cameron spent the time between Titanic and Avatar developing his own cameras and motion-capture technology for the sci-fi epic, but the film still faced a multitude of problems throughout production.  He hasn’t forgotten the tough road as he now faces the task of doubling the workload:

“It was this kludgy prototype the first time,” Cameron said, borrowing an engineering term for clunky. “We always knew as we were going along, this isn’t really working, but we’ll fix it for the sequel. The first film just about killed us, and now we’re gonna try to do twice that much.”

The hoped-for 2014 release of Avatar 2 is no longer a reality, but the article notes that Cameron expects to begin pre-production on the sequels in January with an eye towards releasing the first follow-up sometime in 2015.  Even so, this is James Cameron we’re talking about so I wouldn’t exactly take those dates to heart.