I had the priviledge to see a VES (Visual Effects Society) screening of the film "Captain America: The First Avenger" a few weeks ago, which was held at Framestore. Afterwards Framestore and Double Negative talked a bit about their involvement on some effects shots.
I really love to hear the inside scoop on what was worked on, the challenges, difficulties, the joys and the humour that they all have in achieving their shots. And all their work was seamless! So hearing what really went into creating the 3D and 2D compositing shots excited me.
The audience settled down for a 3D stereoscopic screening, minus popcorn, but with free drinks in hand :)
Right after, Framestore jumped in and explained their worked on about 80 shots for their sequence. They did some tricky nose replacements using NUKE's 3D projection workflow. They had designed a custom pipeline for prior shows utilising their matchmove track data and object track information to speed up roto and cleanup techniques before the CG new face was composited on top. I made it sound really straight forward, but it was a technique they developed for some earlier films like "The Dark Knight" for the two-face character directed by Christopher Nolan, and "Where the Wild Things Are" directed by Spike Jonz, which I actually worked on when I was at Framestore. On a side note, it was a great project to have been a part of since I had grown up with those books as a child. Spike was very involved in the whole post production process and was at the company quite often working directly with artists to achieve his subtle animated character look, which he was thrilled with in the end.
Anyway, back to the story... this tracking and cleanup projection techique used then, got prefected even more and streamlined into their new NUKE pipeline to make the process very interactive for compositings compared to the past when using Shake software. In the end of their look development process for 'Captain America', they only ended up replacing very little of the original face with CG, hence keeping it even more seamless and realistic since more was based on the real plate.
He mentioned briefly using articulated roto mattes and splines to be used in the rigging of the facial parts to help build, and eventually integrate, all the facial detail needed to keep it photo real.
They also unwrapped the textures to ease the cleanup 2D work necessary to remove unwanted foreground elements. That made the 2D compositing cleanup and paint work much easier. He emphasised the show was quite 2D driven, which was nice to hear since these types of shots are generally considered 3D heavy to generate the many elements. They had a RenderMan pipepline that has worked for them very well for the past show. In all very successful in my eyes!
Next a team of artists from Double Negative spoke about their work on the film. After showing up right after the screening finished, coming straight from the nearby pub, they very informally shared their pretty crazy schedule and juggling of shots necessary to meet the client's deadline. Among the sequences they worked on were the Alphine Pod 5 and the arctic sequences. They delivered about 500 shots, and about three quarters of them got cut after the final comps were done! That's sounds quite crazy. And the schedule change from six months being compressed into about half the time. The final composites needed to be in stereo, some where dimensionalised, and some were natively rendered in stereo from 3D. They explained there were about 55 layers on the average for a lot of shots for the stereo conversion! One thing they mentioned several time was the excellent quality of the sets on the shoot. To start with great material from the shoot sounded like a great perk and inspired everybody even more to create cool imagery. We found out the director's style of working did not include a lot of previsualisation fort the 3D/VFX shots. He worked more on the fly which can sometime be tricky to plan out a complex shot in advance. But they got in a rhythm with his style and produced a lot of excellent shots in a short time.
In the end, their casual talk ended up being fascinating in how they got it all to work in the time frame, and still make it look seamless. For me that's a huge inspiration and respect goes to them in pulling it all off beautifully!