Having trouble animating locomotive arm...

[subgeniuszero]

Hi guys. I'm new around here - and new to Maya as well - so please, be gentle!  I'm trying to work through the "Introducting Autodesk Maya" tutorial book (the chapter where you animate a locomotive using bones and an IK chain), and I'm getting stuck and very frustrated.  Basically, I cannot get the steam-pump arms of the locomotive to animate properly; one end is supposed to stay stuck in place (at the pump assembly) and the other end is supposed to move with the wheel when it animates (y'know, like a regular locomotive). Problem is, whenever I create the joints for the pump-arms, the arms want to go flying up in space whenever I move the wheels, instead of one end staying stuck to the pump. I've tried creating IK handles at either end, and setting keyframes to make them "stick" in place, but to no avail; they still go flying in the air. Can anyone help me get this thing rigged correctly? I'm enclosing screenshots of my Outliner, perspective view, and a reference to the book (page 440). Here's the procedure I'm following:

1. Load the locomotive model.
2. Select the pump-arm in perspective view.
3. Create a joint where the arm meets the wheel (root); create another where it meets the pump; group the pump-arm under the first joint and the first joint under the wheel.
4. Create an IK handle at the pump-end.
5. Create a transform key at frame 1 for the IK Handle
5. Rotate the wheel — pump arm goes flying up still!!

[subgeniuszero]

Hey guys,

I wrote in the other day with a problem trying to get a locomotive arm to animate properly in Maya using IK instead of constraints, and I've almost got it licked. The only problem is that now when the wheels rotate and the piston arm pumps, it doesn't go all the way to the top of the wheel on the wheel's upward rotation, and the "head" of the piston doesn't want to stay "glued" to the pump-action arms. I've tried adding constraints — point, point on poly, geometry — but nothing wants to make the arm "stick" to that section of the wheel the way it's supposed to, nor will the "head" of the piston stay stationary at the pump end.  Any thoughts on this? I'm posting a dropbox link to the Maya binary file, in case the forum won't let me post the actual file, and in case anyone wants to check it out for themselves . . . There's a Driven Key set for all the wheels so that they all turn when "complete_wheel_09_master" is turned using the slider under its Extra Attributes section, and the piston arm is parented under the first joint under the wheel.

Thanks ahead of time if anyone wants to take a look. I'd be most grateful for any assist!

Yours truly,
Andy H.

https://www.dropbox.com/s/n7cakzv7khtalp3/locomotive_01.0071.mb

[Steve_Curley]

Please try and keep all posts on one topic in a single thread. Your threads have been merged as multiple threads on the same topic are not allowed.

[subgeniuszero]

Well, it would seem that I'm getting closer!  The front locomotive arm now animates like it should, or at least sort of like it should, as you can see from the screenshots I've included.  However, the animation still isn't right.  As you can (hopefully) see, the front locomotive arm is animating, but it's not synched to the wheel correctly; it does indeed bob up and down as it should, but the placement of the "head" of the piston — on the driving wheel in the center — is not correct.  How can I get this thing to line up properly?  I've tried using constraints, but that just makes a mess of things — or, maybe I'm not doing it right?  Can anyone please help me with this?

[muzipcan]

Are you looking for something like that?

[BradClarkRiggingDojo]

I have a tutorial on this on our Rigging Dojo youtube channel.

https://www.youtube.com/watch?v=goKGOwgh52I

Give it a look.

[ikincidersim]

thanks for rigging Dojo tutorial...

It was quite useful..

Can I ask a question?

I have a stairs in my scene.. I need to visible every steps over time.. from 1 to 300 ... Do you know how can i arrange their visibility in a short way!!!