The film Asterix and Obelix: God Save Britannia brought together a team of 82 people at MPC (formerly Mikros Image) supervised by Guillaume Terrien (VFX) and Laurent Taillefer (3D), including some sixty graphic artists divided equally between 2D and 3D specialists.

We produced 350 shots VFX for the film, including all the land environments – namely the Breton and Gallic villages, London, and the stadium – the final battle sequence with the Romans, and the scenes in the cellar with the Roman soldiers.

Our main challenges were stereoscopy, the many crowd shots, and of course, taking over a project already started by another studio. The team worked through a pipeline of Maya, miCrowd (Mikros’ proprietary software), Arnold, and Nuke. Mudbox was also used for modeling and some texturing.
“We used some models, textures and rigs, photos and measurements from the shoot, plus some matte elements. Generally speaking, we had to re-edit everything, if only to integrate the assets into our Arnold-based rendering pipeline. The biggest challenge was sorting through the material to determine what we could reuse.”

Crowd simulations were one of the keys to the project for the team. “These simulations were used in full or as a complement to the real actors that were present in the image. We worked with miCrowd software, an in-house integration of tools developed by Golaem (www.golaem.com). To create the agents, we used models, textures and animations captured on set. During the battle, most of the environment is matte-painted, which led us to treat the scene as essentially full 3D. The shots with actors were more complex to process, mainly because of stereoscopic issues. We ended up with atypical optical distortions between the two images (right and left eyes). Compositing had to intervene to realign the elements correctly.”

The matte paintings and set extensions were created from 3D LIDAR scans of the environment provided by the production for the majority of the locations. In addition, the team had numerous reference photos of the real part of the image to obtain an accurate 3D model. “We then modelled, textured and lit the elements to be added (houses, villages, vegetation, etc.) in order to obtain a usable stereo image. Our matte-painters corrected certain elements of the image, and these were reprojected onto the 3D models. In essence, this was mainly a 3D approach. The backgrounds were also projected, but from a single image, and therefore in a more traditional way. At this distance, the impact on the stereo was more limited.”