Really cool stuff I found on Kenny Roy's Blog. A list of super cool Mel Scripts for Animators.
1) tweenMachine: create ease in/out poses by defining a percentage between prev/next keys.
2) llShowAnimCurves: isolate curves in the graph editor, for example show only Rot X curves for all selected controls (unfortunately, it doesn't seem to work well with our rigs at work, but it's awesome when it does work)
3) axisControl: easily switch between object/local/world space for your manipulator tools, window only visible when tool is selected so screen space is cluttered as little as possible. It's odd that you can't drag the window around, but you can sort of move it by dragging the corners around and re-size it into place.
4) zooGraphFilter: I found an alternate to llShowAnimCurves that will let you isolate just the curves you want to look at in the graph editor. This one works just fine with our rigs at work so if you had a problem with the other one try this.
5) llScaleKey: scale curves in the graph editor by arbitrary percentages, and choose whether to anchor min/center/max of value/time. The only thing I don't like about it is that you can only do one curve at a time because the anchor is absolute for the entire selection, not relative to each individual curve. The next time your supervisor asks you to reduce the up/down bounce of the hips by 30% you can do exactly that.
6) dnAnimationTimer: tap out your timing with the mouse, prints the click-frame numbers and frames since last click-frame in your script editor. Works for any frame rate (FPS) setting.
7) mtAlignTool: choose which channels to align in trans, rot, scale, x, y, z. Select target item, shift-select the one you want to move, then hit apply. If you want to match multiple frames just go to next key and hit apply again, etc.
8) dkAnim: export/import animation. Creates a text file that you can edit (replace name space, paste to a different character, etc) and allows you to specify only certain objects/frames.
9) chinaMarker: Helps when you really want to plan out your animation in a traditional fashion, but within Maya. It allows you to draw, frame-by-frame, on your screen and set holds like you would on an x-sheet. You can actually create pencil tests in Maya! The learning curve is a little steep, and it's locked to the viewport instead of world space so you can't move the camera after you'd drawn.
10) phantomWindow: creates ghosts, but it's better than the maya one because you just pick which specific frames you want to create the ghost on and you can specify colour, show/hide, etc. Remember you can make a phantom of anything, not just geo. I use this in games a lot. Say I need the character to rotate 90 degrees and end in the same pose. I can't simply rotate the character's world control, because then I'll have to counter animate all of the foot contacts. I can make a phantom of my rig, rotate it as a group, then use something like mtAlignTool to snap each control of my rig into it's end position.
11) llUpdateMotionTrail: updates motion trails more reliably than maya does and allows you to easily manage multiple trails, set colours for them, etc. Note that this isn't actually a new type of motion trail, just a way to manage existing ones.
12) llResetChannels: Sets all of your selected controls back to their default values. It's a quick way to "zero out" an entire character (and works even if the default value of a channel is non-zero), or just one control.
13) ackDeleteRedundant: This reduces the graph editor clutter by deleting any keys that are identical without changing any of your keys. For example if the X axis has four identical keys in a row, this script will remove the middle two and leave the "bookend" keys so your animation won't look any different.
14) ackSnapAnimation: Takes current selection of keys and offsets its values so that it lines up with the left neighboring key. One creative use for games is to use the same animation on a different pose. Just set a new pose on frame -1, snap the anim to match, and voila - though the poses can't be too different or the animation won't look right. You could also use it for pasting/rearranging bits of animation and keeping your animation relative to it's neighbor. (Since switching to Maya 2011 I've pretty much ditched this for Anim Layers which are much more powerful)
15) alienCycle: Ever need to make your cycle longer? Maybe you used pre/post infinity cycles in the graph editor, but now you want it changed to actual keys so you can vary the cycle. Alien cycle will help you with that. Tell it how many cycles you want and it will duplicate your keys for you.
16) cycleAnimCurve: Want your cycle to loop smoothly? Well I haven't found a better method then manually adjusting the tangents on the first and last frame simultaneously so they match, but this one does a decent job of approximating that process for you so you can iterate on it more quickly and just do one pass at the end to get it really perfect. It copies the value and/or tangent angle from the first frame to the last frame, or vice versa, or an average of the two.
17) Reckey: I don't use this one all that often, but it can be really useful for blocking in animation or for adding some handheld feel to a camera (ideally on a separate anim layer) Basically, you can drag an object around in the viewport with your mouse and it will record that motion in real time. You probably want to rehearse the motion and timing you want a few times and then set your timeline to start in the negative frames to give yourself a bit of lead-in time so you can start the motion right at the beginning of your shot.
18) madRecentCrashFile: Maya never crashes, right? Ha, I wish! But if you're lucky Maya will save a backup of the current state when it crashes. The only problem as that these temp files are hard to find afterward. Just add "madRecentCrashFile;" to your usersetup.mel file and it will add a list of recently created crash files to the File menu. The next time Maya crashes like this just re-open Maya and load the latest crash file from the File menu.
BONUS! (a couple of awesome hotkeys for retiming your animation in the graph editor and time slider respectively using just the left and right arrow keys, courtesy of TJ Phan: