CIS Vancouver- Invictus

Fourteen years ago, newly elected South African President Nelson Mandela was faced with the challenge of unifying a country emerging from the turmoil of Apartheid. To unify the South African people, he turned to the national rugby team to win the 1995 Rugby World Cup and inspire the nation. Director Clint Eastwood brings this true story to the big screen in Invictus and CIS Vancouver was chosen to populate the South African stadium with a crowd of thousands for all stadium shots.

CIS Vancouver already had experience creating crowds for the big screen although the grandeur of the stadium in Invictus would require a level of control not available from their existing in-house system. They needed a system that would give them maximum control over demographics, actions and spectator appearance. Therefore, CIS decided to develop a custom crowd system that would allow them to work procedurally using Houdini at the core.

“Houdini was the hub of the Crowd system while Houdini’s Mantra served as our primary renderer for the crowd/stadium work” says Peter Bowmar, Head of 3D and Technology at CIS Vancouver.

To achieve specific control, Houdini’s ability to manipulate data on point clouds proved invaluable. For instance, a group of characters could be selected using standard Houdini point-selection tools then converted into South African supporters by using attribute values to make changes such as changing shirts into jackets, or blue textures could become green. They could even change specific parts of the crowd’s response by changing their pose-caches all the while timing their behavior to the action in live plates with out returning to Massive for new simulations.

“We knew that Houdini gave us the control we needed with a combination of surface operators and shaders,” Peter adds. “For more complex dependencies that defined appearance, such as making sure women didn’t have beards or South African supporters weren’t waving a New Zealand flag, we used Python operators and Houdini operators wrapped into digital assets to define the logic. The recent addition of tighter Python integration in Houdini proved to be very important in this project.”

At various times during production, there were shots that contained up to a staggering 30,000 agents at a time. This was all done in a very user-friendly way using Houdini Digital Assets and Python scripting. At the end of the project, CIS had over 300 unique digital assets in their crowd pipeline.

“There are over 300 shots in Invictus with crowds and stadiums that were produced using the crowd system and rendered using Mantra. Mantra's site-license was key in helping us decide to move forward with Houdini and Mantra, as the cost savings over other rendering solutions was significant” says Peter. “Mantra's openness through C++ plug-ins, the VEX shading language and the responsiveness of Side Effects support made it an easy choice for rendering.”

Given what would seem to be a daunting task, the pipeline developed by CIS Vancouver for this project provided them with freedom to make changes to behavior or demographics due to the procedural nature of Houdini. This was especially important as it allowed the client to request changes early in the morning and have visible results ready by the afternoon. If they decided that a group of characters should remain cheering, but change their clothing or gender, they could do it without altering the behavior. More importantly, the changes they would make were non-destructive.

“The procedural nature of Houdini and the ease of creating, maintaining and editing digital assets is a huge benefit in a production environment” says Sean Lewkiw, CIS Vancouver’s Digital Effects Supervisor. “This is one of the main reasons why Houdini worked so well for building our crowd tools for Invictus.”