When your bird is actually a fish

Behind those CG birds in ‘The Core’, and how one of them was actually a…salmon! An excerpt from issue #4 of befores & afters magazine.

The addition of a flock of CG birds is a common trick in visual effects filmmaking to help ‘sell’ the shot, to give it some life, to lend it some scale. In the latest issue of befores & afters magazine, several VFX supervisors, artists, researchers and other players in the history of CG birds, break down these kinds of bird shots.

One of them is Daniele Colajacomo, who worked on The Core, where his studio 3DSite crafted flocks of CG birds for the London sequence. Incredibly, one of the birds added in was actually a salmon, placed into dailies as a joke, but which then remained in the final film. Here’s the story as printed in befores & afters magazine.

Inside issue #4.

From page 43:

One action-packed (and bird-packed) sequence in Jon Amiel’s disaster movie The Core (2003) sees altering Earth conditions affect the behavior of thousands of birds, mostly pigeons, in London’s Trafalgar Square. Real pigeons plates were filmed and then also augmented with CG bird flocks handled by 3DSite that terrorize Londoners.

“I wrote a particle system that also included obstacle avoidance, with the related change of animation,” details Daniele Colajacomo who was President of 3DSite on The Core. “We animated hero paths for the birds to follow as a flock, each general direction had a few extrapolated paths which the hero birds would follow. When faced with an obstacle, each bird had a random possibility of hitting it, more or less according to the particular scene. We also had background, midground and foreground flocks each with their own paths and behaviors.”

“In terms of modeling, we did model a single pigeon, including wing feathers, and textured a few variations. We then animated the various ‘modes’ of the birds, including hitting and falling, and had the particle system drive the animations and transitions.”

To establish the right kind of flocking behavior, Colajacomo remembers hanging out at the end of Sunset Boulevard in Los Angeles for many hours shooting pigeon footage, then studying it. “There were not any particular challenges besides rendering all those pigeons back in the day for a small facility like ours. For the rest, our mind does a lot of the rest when it sees ‘pigeons.’”

“In fact,” continues Colajacomo, “in one particular shot, as a joke, we rendered a salmon hitting an obstacle, pretty much in full view, thinking of getting a laugh out of the director. The shot went through two levels of reviews and was approved before we pointed out the salmon. The director ended up leaving it in the movie and now there’s a shot there with a salmon hitting a glass window! To me it seems to indicate that movement is even more important than shape, and once you buy into flocking and disoriented pigeons, you won’t even notice if they’re pigeons or fish!”

Get issue #4 here.

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