How did it feel to play that scene?

It was very moving. Of course, in classic filmmaking style, we did it two-thirds of the way through the shoot. Karin Konoval, who plays Maurice, and I both knew that it was going to be a big day. It was quite somber. There was a real sadness, because we have all lived with these characters for a long time now. I’ve played this character from an infant, which is very rare.

I still feel the loss of playing such a great character, which I don’t think I’ve felt before. Gollum in “The Lord of the Rings” was a huge part of my life, but I knew I would play him again in “The Hobbit.” This was different, I think, because I had played Caesar for his entire life.

Is this really the end of the character? Could there be a prequel, for instance?

Working with Rupert Wyatt and Matt Reeves, the two directors who have done these movies, has been pretty special. I have spent more time with Matt, as he did the last two, and his grasp of that world is so thorough, and he is so passionate about it, that if he were to come back and work on something like that, I would hope I’d have the opportunity. It’s not a world I’d let go of lightly.

Of course, with performance capture, you are not limited to a physical persona. You’ve played baby and elderly Caesar, but you could also conceivably play, say, his son, in a sequel?

As an actor in the 21st century, you have a tool — performance capture — that enables you to transform into anything you want to play. That has been a huge thing for me, and a central part of what drives me as a creative person. So yes, there have been loose talks about how that might manifest, but nothing concrete. Some other incarnation perhaps; that is all possible. It feels good that it’s the end of Caesar’s journey, but if I were to go on generationally, as it were, that might be interesting.