Motion Editor: KiHyun Kim

Hello my name is KiHyun I'm currently working at Weta Digital as a
Motion Editor.
before I joined Weta, I worked at Animal Logic as a Motion Editor on
Happy Feet and Photon vfx Australia as character TD.

The Motion Capture (MoCap) department have 3 parts which are Motion
Capture, Motion Edit and Facial.
basic process of our department is apply Motion Capture data which has
approved by the Director to characters in the film then synchronies with
previs perfectly.

We use Autodesk's Motionbuilder, Maya and Giant Studio's Nuance.

So many people understanding what is Animation but not Motion Editing,
even many Weta Digital artists in other departments often asked us what
is Motion Editing.

When actors are acting, every maker's on their body is recording to
computer, which is called RAW data. This capture date may need an
artiest eye over and/or edit may be needed, for example, during capture
process, actors are not wearing same costume which will be showing in
the movie. if their hand on the chest, we should have proper idea how
this actor's motion will react with proper costume in the film. also in
few years of making films, all the modelings and riggings are
progressively updated, so there may be time when we need to tweak edits.
All this to enhance and
match the turn performance.

Feature Film's frame rate is 24 frame per second. We capture and edit at
60 frames per second it's roughly 3 time more accurate. In James
Cameron's Avatar, the MoCap department took care of all the motion
except ears and tails which human can't act. During editing, we match
our characters motions against actors movements exactly same with raw
data. If we simplified the data it would look like key frame animations
and would not be true to the actors performance hence would not be
approved by the Animation Director.

Another challenge was the terrains, 3D with Capture terrain had some
differences. We needed to tweak the motion to match, characters to sets,
lensing and proformance... Deliver to Animation. With Facial, Weta
Digital has it's inhouse tools for tracking and solving, this technology
allows the artist to
control very subtle movements on the face based on muscles' structures.
And lets not forget crowds. Heaps of crowd shots on avatar, we did most
of the
crowd work due to the complex of motion, close ups and terrain. Massive
department helped for more distant characters.

One shots which I did have around 200 characters, every characters were
putting their hands on other's shoulder. When I received the raw so many
characters were over lapped and intersceting, not only this I needed to
edit all characters' feet to contact the terrain and needed to adjust
some characters head and neck motion for hair and cloth symulation more
easily.

I will remember this as a great moment in my life. The privilege to be a
part of something special, working in a beautiful New Zealand with
worlds best artiest at Weta Digital and on the James Cameron's Avatar.