View Full Version : Nla

08 August 2002, 08:21 PM

08 August 2002, 09:53 PM
Non linear animation, the way I'm reading it (someone correct me if I'm wrong) is rules based rather than keyframe based.

For instance, set up an object to react to the proximity of another object.

It's sort of an If/Then statement for animation.

08 August 2002, 10:01 PM
I thought that was procedural animation? A-la Houdini. As I understand it Non Linear Animation is the ability to have animations on various tracks, while being able to blend between & non-destructively stretch, move, duplicate etc the various tracks of animation.

Example: say you have a fighting character. On one track you could lay down some base animation of him bobbing up & down & flexing his fists. On another track you could animate a punch. You could then slide that punch animation anywhere in time you wanted it, & it would blend with the bobbing animation track. You could then duplicate the punch track & move it foward to make 2 punches, all seemlessly & non-destructive to any other tracks of animation. :beer:

08 August 2002, 03:38 PM

Like I said, someone was bound to correct my mistake :D

08 August 2002, 09:05 PM
:D LOL theres just too many buzzwords to keep track of huh? ;)

08 August 2002, 09:55 PM
NLA has been swapped around as a catch phrase for a few months now as a sales tool. I remember when Lightwave first started touting it, and no matter how hard I looked, I couldn't find an explanation of what it was.

I'm still not exactly sure.

08 August 2002, 10:23 PM
its just the grouping of animations, where any one group can be 'slid' in time without affecting any other group (buzzword - 'non-destructive') and all the groups animation is blended together to create the characters finished motion. The 'Non Linear' part just comes from the same reasoning as 'Non Linear Editing' - you no longer have to start at the beginning, & animate one set of animation data through to the end. You could set a couple of poses at the beginning, then go to the end & animate some facial expressions, then go somewhere in the middle & animate a hand gesture with some more facial animation. You can then change your mind & drag the later facial animation so that it is just before the earlier facial animation, it will all be merged together so that one expression smoothly blends into the other... :)

08 August 2002, 12:59 AM
that's still keyframing, though... I don't get the "non-linear" part of that equation. It's still keyframed motion on a timeline.

08 August 2002, 01:22 AM
Aye it is, keyframing is still the same. This sort of introduces another level of control above keyframing, which is the non-linear part.

So to animate an arm lift, you would still keyframe a position key of the arm control down low, go foward in time, add another position keyframe with the arm control up high. There is your normal animation process right? Its not until now that the NLA comes into play, forget about the keyframes for a sec & think about that block of motion. You could grab that block of motion, slide it in time, stretch it in time, duplicate it so he raises the arm twice, reverse it etc etc.

Now you might be thinking 'I could do that by moving the keyframes anyway', this is where the important side of NLA comes in. If you already had further animation set up on the arm control, any moving, stretching or duplication of these keys is going to affect the function curves leading into & coming out of other keys on the same object. With NLA those existing keys & function curves on that object are in another 'group' so they are unnaffected. The animation will still change, because it is now blended with the new motion you have just put in, but if you then remove that motion, or slide it to another point in time, the previous animation will be exactly as it was before. Thats non destructive, Non Linear animation - you can mess around with various poses & motions, experimenting as much as you like, avoiding a lot of problems like your curves suddenly overshooting your key because you moved one key a bit closer to another...

whew, I hope thats clear - I tend to ramble a bit :)

08 August 2002, 04:38 AM
Seperate animations and mo-cap animations can be easly blended.

You can make mutiple derived personalities from a couple of personalities.

Like If saw MIB2. You can see tiny aliens in locker. They were hundreds. Animators only animated couple of them others are derived using a NLA system.

There are several advantages of a true NLA sytem.

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