In Terminator Salvation, judgment day has passed and the robots have taken over the world. T-600 robots are hunting down and capturing humans and T-800 robots, made famous by Arnold Schwarzenegger, are waiting in the wings. And a new breed of man-machine has been created with a human heart and human brain harvested from death row inmate Marcus Wright.

With the movie populated with so many robots, Asylum VFX was brought in to create and animate the T-600 and Marcus cyborgs. Given the detail needed to set up a realistic robot, Houdini was used for both the rigging and animation. Asylum chose Houdini because of its digital asset pipeline which would allow several different people to work on the same rig at the same time making it easier to bring all the parts together for final output.

The main rigs started were initially built using the Auto Rig tools included with Houdini. This default rig was then customized to meet the demands of the match movers and the specific physical traits of the different cyborgs. By using the auto-rig tools, Asylum was able to work at their own pace and did not have to map out every contingency ahead of time. This made it easier to manage the development of the rig and avoid overdeveloping features that were not needed.

“We knew we were never locked down with a specific solution,” said Jeff Willette, Technical Director, Asylum VFX. “Houdini Digital Assets let you experiment with different techniques and flush them through the entire pipeline easily and know you can undo or modify them later. Often, we would put a temporary feature into the rig after testing it out, realize that our quick solution was good enough for the final effect.”

By using Houdini, Asylum could update rigs as needed and everyone was instantly able to use those new features without having to think about it. The team was able to make many changes to all the rigs that and the changes happened seamlessly throughout all the shots. This kept every shot consistent, and CG supervisors never had to worry about someone using an outdated version of the rig.

Working with the Match Move Rigs

While the rigs were being developed, animation and lighting could start early. The Auto-rig tools split the rig into an animation or match move rig and a deform or Endoskeleton rig. The match move rig could be used by animators to start setting keys without having wait for the Endoskeleton rigs to be "finalized". Once a Endoskeleton rig had been detailed then it could be plugged into the match move rig and rendered. This way, turnaround time from design changes of the models to final renders was minimal.

“All of the matchmovers were brand new to Houdini, most of them had never launched the software before,” said Willette. “There were basic questions that popped up but we were getting results from the whole team on day two. After a few weeks, they were seasoned pros and even taught some of the experienced Houdini users a few things.”

At first, the matchmovers were concerned that the workflow would be different from how they were used to working in other packages, but once they got used to Houdini’s animation tools and the features of the rigs, they were quickly up and running. If there was ever a limitation in the rig, the digital assets could be easily updated to accommodate their needs.

Nested Assets

Because the robot rigs were made up of different body parts, each rigger could be in charge of a specific internal component. These were set up as nested digital assets which could be inserted and updated at any time. Early on, it was not possible to determine what robot parts were going to be seen on screen so Asylum waited until the matchmoving stage was in place. Then as the film progressed and shots were narrowed down, the team could decide which components were actually needed and concentrate their efforts on those specific areas.

Using nested assets, it was easy to update the rigs without compromising animation that was already completed. For example, a few shots of Marcus were matchmoved before the hands were rigged. Once Asylum got the hand model finalized, the rig was updated with animation controls for the hands and fingers. The arms had already been animated, and the animators only had to add the hand animation to finish up the scene.

"Creatively and technically Marcus was a challenging but exciting task, we had to seamlessly blend live action plate, practical appliance, 3D flesh and soft tissue, 3D nano substructure and a fully articulated and animated 3D metal endoskeleton,” says John Fragomeni, VFX Supervisor, Asylum VFX. “Our prime considerations for using Houdini on Terminator Salvation for our character 3D work on Marcus and the T600 were the quality depth of our artists and the flexibility the pipeline provided. As the VFX supervisor it was comforting to know that we could make last minute intuitive improvements without any adverse impact on the workflow."

For the T-600 and Marcus shots Asylum used a combination of Houdini and Renderman. Houdini has a strong connection to RenderMan built-in therefore the team could have everything in one package. This was a huge benefit and made it possible to limit the amount of interoperability needed. With Houdini’s digital asset technology, everyone from matchmoving to lighting knew they were always working with the most current versions and when new animation was published it would be instantly available without conversions. This streamlined workflow made everyone’s life easier and let the artists focus on making the robots as cool as possible.