|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.
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January 9, 2006