Maya 7 was released during SIGGRAPH last year, and many
consider it to be one of the most remarkable releases to date. The
guys at Alias made some updates to the existing tools, improving
the functionality in some of them, however everybody agrees that
one of the most important additions to the software is the ability
to use MotionBuilder's Full Body IK system. Actually this was an
expected move considering that Alias bought Kaydara a while ago.
If you are familiar with Motion Builder you know how the system
works. Howeve,r I will assume you are new to Motion Builder so I
will discuss a little about the Full Body IK (FBIK) system.
Basically the FBIK system creates an IK solver that runs through
the whole body to help you create natural poses easily. For
example, you can pull your character's hand downwards, and your
figure will crouch naturally to touch the ground. Another example
is that the character will bend or twist its spine if you pull his
head. Video 1: Natural motion with FBIK The other
interesting thing about the FBIK is the use of
effectors. If you are familiar with advanced rigging
you will know that it's easier to create handles for your rigs, and
effectors are actually handles. You use them to rotate or translate
your body parts. What makes FBIK effectors so special is the fact
that you can "pin" the rotation and translation of any body part.
For example, imagine your character kneels down and then you
animate from there. If you use a standard rig you have to
counter-animate the hip to make sure the knee stays in position. Or
maybe your character puts their elbows on the table and starts
gesturing with both hands. You'd have to make sure the elbows don't
"slide" on the table. Now you can just pin the knee or elbow
effector, and animate from there. The rest of the body behaves
naturally around that locked point, so if you then move the hip or
spine the knee and elbow will stay locked in position. You can pin
any body effector, which means you can lock any body part you want.
Video 2: Pinning body parts For those
familiar with the Trax editor, let me tell you that the FBIK system
is completely linked with the Trax editor via character sets. Your
complete rig becomes a character set and the body parts are stored
in sub-character sets. This means you can store animation clips for
the whole rig or just for specific body parts and combine those
with new clips. There is a slight problem with the new animation
system, and it's the fact that you have to know what you are doing.
For example, if you use the standard "set key" you will run into
problems in the long run. The "auto-key mode" will also cause you
problems because the character set will automatically set a key on
the different body parts and you will end up with a really big
mess. The FBIK system includes its own keyframing tools and those
should be the only ones you use. If you thought you would never
need standard rigs again, think again, for I have found a lack of
multi-limbed creatures support. Say you modeled this very nice Goro
character from Mortal Kombat, or a centaur, or maybe a
man-spider character. You will have to use standard rigs for those
because the FBIK system looks for a specific hierarchy for either
biped or quadruped characters, so more than 4 limbs is not
supported.
Setting up the FBIK rig is very easy. First you have to draw the
standard single-hierarchy skeleton (no floating bones), and then
you have to name your bones so Maya will be able to read the
hierarchy. After you've done all this you add the FBIK with the
click of a button. Then, you can add more effectors where you need
them to customize your rig and you are done. You get a fully
functional rig in less than half an hour. Even with these small
limitations, this new animation system will surely become a common
tool for animators and riggers. It takes a while to get used to the
system but that happens with any new program you learn. As I said
before, Maya 7 includes some really interesting additions but the
FBIK system alone is worth the upgrade. HOW TO PLAY THE
VIDEOS:
- Windows users: simply use the Windows Media Player
- Linux users: The Xine video player can playback WM videos.
- Mac users: there is a MAC version of the Media Player at
Microsoft's website
- Information on Alias' Maya 7
 Animation Alley is a regular featured
column with Renderosity Staff Writer Sergio Rosa [nemirc].
January 9, 2006 |
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