• Pixomondo

    CGSociety :: Technology Focus

    30 September 2011, by Paul Hellard

    Mohsen Mousavi and the dedicated Pixomondo team have built a great VFX and technology department from the ground up over the past five years. From micro designing gigantic shots on a conceptual and technical level to macro managing the FX team, Mousavi has had a major role in creating of some of Pixomondo's best work. Mousavi is currently working as FX supervisor on George Lucas' ‘Red Tails’.


    “Zack Snyder loved the work we did on ‘The Red Baron,’ which included lots of complex flight choreography and dog fight sequences in an active war environment,” says Mousavi. “We were approached by the production company to accomplish the entire WWI sequence including an extreme sequence of a zeppelin crash.”


    Pixomondo supplies visual effects production and supervision, CG character creation, 3D animation and pre-visualization for feature films, television, commercials and live media. The VFX company has a global network of facilities in Los Angeles, Burbank, Toronto, London, Shanghai, Beijing, Munich, Berlin, Frankfurt, Hamburg, and Stuttgart, allowing it to provide services to the global marketplace.


    Each of the facilities is concentrated on a certain aspect of shot production. Sometimes a shot is handled through four or five facilities. Therein lies the challenge to maintain communication both in the micro and macro management during the shot production.


    The Berlin Pixomondo studio is focused on finalizing heavy FX driven shots. One of the most challenging sequences we worked on was the collapse of the zeppelin in ‘Sucker Punch’. The idea was to show as much of the complexity of the structure. Also, we needed to build it in a fictional way so it could be destroyed realistically. We used cebas thinkingParticles together with many other inhouse tools and scripts to rig the underlying structure through a very cleverly rigged joint system which is done entirely as a logic driven procedural system.


    cebas thinkingParticles (TP) plays a very important rule in any heavy driven FX shot accomplished at Pixomondo. It is an open framework which has focused on procedural, non linear, and logical particle driven effects.

    Workflow
    The TP procedural joint system, shape collision and the logic-driven Voronoi tessellation has certainly changed the way things are done compared to a couple of years ago. “We were able to rig the entire structure of the zeppelin and all its Rigid Body Dynamics constraints through logical rules and then pipe it as an asset through different shots,” Mousavi explains.

     

    By preparing the underlying structure assets to share in different shots, the Pixomondo crew could grab a proxy structure at any time and easily import the assets related to that proxy from the server. Both ends of the proxy were marked so they could access those polys in TP and create joint positions from there. “We developed a node in TP which would visualize the data flow and joint connection as an OpenGL line in the viewport,” says Mousavi. “We spent a lot of time figuring out the best way of controlling the energy flow in the joint network and how we could mimic the reality as much as possible. The setup was done so that we could increase the distance, to which every proxy could have a joint relationship.”

     

    Using a masking network in thinkingParticles, the Pixomondo crew could control the stiffness of different portions of the structure as well as the condition on which it would rip apart. Having the system as an asset they could bring in the proxy structure and pipe it through the network and quickly have the first version laid out. They did many versions and different combinations, each time getting more ideas about how to make the event even more dramatic.

     

     

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    Once the base proxy simulation is done, the cloth rigger is run. This would analyze the entire network and rig every patch to its corresponding structure underneath with dozens of group constraints. This would be impossible to do manually. The cloth rigger has a lot of toolsets that allow designing of tears and dynamics on the cloth on that many patches at once. “Having the cloth approved we would convert the proxy model of the structure to a high res model. The fire and smoke was sometimes a combination of over 40 FumeFX grids per shot which were managed through our in-­house FX manager,” says Mousavi.

     

    Prior to using thinkingParticles, Pixomondo were using different techniques to deal with particle or rigid body simulations. Multi layer caching framework has made it possible to break an effect into many different components and enable more artists to work on the same shot and sometimes on the same element of the shot. “thinkingParticles, as a unique framework, sits at the heart of the FX department at Pixomondo,” Mousavi says. “It has become the foundation of many different technologies we have developed and utilized during the past years. It has been an amazing journey to be part of the development of the software. The SDK has enabled us to utilize many ideas in the shots and integrate many different in-house solvers, which binds nicely with the entire standard thinking particle logic and is extremely scalable. For simulating fire and smoke we used Sitni Sati’s FumeFX. We studied many different approaches on how to control the fire and air pressure. The way air leaves the zeppelin and how it grows over the surface and triggers a series of events which are all coupled together through rules and procedural conditions.”

     

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    “On ‘Sucker Punch’, we had the opportunity to test different behaviors of grid base fluid simulation under different conditions. We worked our way through and understood the best methods to how to control an Eulerian flow field. For Pixomondo, playing a major role in such visually stunning project was fun in all aspects. It has been great to be involved on one of the key assets that Zack Snyder used to bring his vision to life.”

     

    "I would love to thank the great team we had that made this happen! Many thanks to Florian Schroeder, Henrik Zähringer, Goran Pavles, Hristo Velev, Marcel Kern, Pieter Mentz, my fantastic producer Franzi Puppe and many others who worked shared a huge passion to make this happen," Mohsen added.

     

     


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