Automatic secondary motion on FK rigs?

Rigging
#1

Hey guys! So, just throwing this out as a question…

The best rigging demo reels (in my opinion) include characters that have some sort of automatic secondary motion hooked up with SDK’s. (aka, you move a bird’s wings up, and after they reach the climax of the motion, the feathers fly up, simulating how feathers would actually interact with air) I understand the principal, but I just can’t figure out how to offset my SDK’s on the timeline. (at least I assume that’s how such a technique is done). I’ve been trying to research it on the internet all night, and none of my search results have given me any information. I really hate asking questions like this on tech-artists usually… (that’s what google is for) but I’m just hitting an information brick wall. (for once the library failed her…) Does anyone know of any good tutorials on this subject? Or is there a quick fix?

I’d really appreciate any leads at all, I’m getting so frustrated. Thanks!!

~Annie

#2

Usually in Maya, particle dynamics with goal weights or soft body dynamics or juggle deformer could be used in combination with spline ik setup
Another option is to use expressions and offset the transformation in time.

Secondary motion setups are overrated even though they do look nice :slight_smile: Animators always end up wanting the control back and if they don’t that part will most likely get properly simmed anyway.

#3

You know, that’s really interesting to note, and I appreciate it. Whenever I’ve animated something, I’ve always wanted full control as well. I was just looking over my demo reel and critiquing it for anything I could beef up further.

I still appreciate the direction though… it might be good to look up. If nothing else, knowledge is power… as that old cartoon used to say.

#4

I’m not sure exactly what you’re looking for here or if you’re using Maya but you can create basic overlapping with expressions by setting the rotation of a particular joint to the value of its parent joint at 3 frames back(or however many you want).

Here’s an example with some MEL in it(there might be a cleaner way to do this, I’ve just started using expressions):
Joint2.rotateX = getAttr -t (frame - 3) "Joint1.rotateX" * 2;

In this case Joint2’s rotateX will follow what Joint1’s was 3 frames ago, and that value will be multiplied by 2. Try it out in an empty scene with a simple joint chain and see if it’s what you’re looking for.

There’s also an entire book on expressions here:
http://www.docstoc.com/docs/412350/Maya-Tutorial---Expressions

Hope that helps.

#5

oooooooooooooh that’s gold! Thank you!!! <3

#6

Are these expressions the same for max?

#7

the logic is the same but the syntax would be different - you would want to use script controllers on the object you’re trying to have secondary motion on

#8

Maya Bonus tools has a nice little add secondary anim tool, lets you pick Hair or Softbody etc. you could look over it and see how they are setting it up. Its fast and works well.

Animators want control but there are lots of times when it is nice to have extra bits simmed then backed back to have animators tweek or fix (just cause its there as automatic , nothing stops you from doing a second layer keyframe rig, and with maya animation layers, you don’t even really need to do a second rig, can just directly override the sime joints with a new layer and blend it in as needed.

All depends on time, the animator and the project.

#9

If you’re really awesome you can add in both. :slight_smile: Give the animator the choice to animate it by hand if they wish to and if the project allows time, but if something goes awry and there’s no time or they just don’t want to do it then they can turn on your rad secondary setup.