Method Tackles the 'Riddick' Mud Demons
"So we changed the way the rigs were generated on the front end. We switched fully to alembic to speed things along. When the animators published, the system would turn out a light rig as well as an accompanying alembic cache [smaller geometry file format]. It's getting improved all the time with some attributes that don't carry through. You have to use a light rig but the majority of what we had in our scene was alembic. It's very lightweight and fast and allowed the lighters to handle lots of creatures without being slowed down."
The biggest challenge, as Rahhali suggests, was movement. The original design was fully upright and it looked goofy. They wanted it to be lower to the ground and it hadn't been done at any other studio where it needed to run or crawl very much. "They wanted scary so we went through several stages and presented David with tests. The animators had a lot of fun getting them to a near crawl. Its arms were extended outwards and looked bizarre. The tail was so long that instead of looping it like a scorpion, we put it back on the ground and used it almost as a third leg. We did another test where it was hunched over and used the tail more like a scorpion and that was successful. In the end, we used all of those, which was bizarre because David didn't just want one way of moving. He liked the low crawling, creepy move; and he liked the more upright moves on a few occasions because, again, they have to be nimble when going over rock."
The most ambitious sequence was called "Demon's Peak." After outwitting and then banding together with his adversaries to survive the mud demons, Riddick gets impaled by one of the pinchers and closes the wound with hot, molten rock, and then proceeds to make his way up a peak, which is all matte painting. However, while climbing the peak, he gets pursued by hundreds of mud demons.
"This whole sequence takes place on a small set with a rain bar," Rahhali continues. "We had to extend it and add water and lightning and other atmospherics and all the creatures he's interacting with. We were driven by Riddick's performance and made it as chaotic and life-threatening as possible. We came on to it late and weren't able to go to the shoot so we were limited by the data that we had. But we made the most of it and were able to get everything sitting in there the right way.
"He keeps making his way toward the peak and the creatures get bigger and badder. One of the mommas attacks him. He throws his weapon and kills her; then he's attacked by one of the dads as he gets to the top. We had to replace everything to make it look like he was holding the corners of the creature's mouth. We used a lot of the rain in the plate, put a mud demon in there and replaced hands. There were several intense over-the-shoulder shots as well from Riddick and the creature along with the creature striking with its tail. The crew comes to his rescue in a space ship and blast the creature in half with a hell fire gun. David left it open for us to develop the look of the blast and I suggested these hot cores going from green to orange that look like copper sulfate and he liked that. There was also lots of goo and blood thrown in as well."
Method also worked on the previous sequences involving the bounty hunters pursuing Riddick on bikes that look like hovering Harleys with turbo thrusts below that interact with the ground.