Maya animation question... IK handles

[Seven]

here is my skeleton, ive deleted the upper body part for now ( im not happy with it) and am just working on the legs.

[svenip]

as i can see, you have an RP Solver IK. so that makes it easy for you just to rotate the ik. in the attributes for the ik you'll find an attribute called twist.

[DesignDawg]

WHat do you mean no access to the manuals?

The manuals are electronic. Hit F1. Manuals.

Ricky

[svenip]

maybe not installed by the admin at his uni, just to save hd space.

we did the same at our university.

[Seven]

yeah the animation tutor didnt install the manuals :( annoying really.

So the twist attribute will allow me to stop it moving on a certain axis ?

If, when im trying to do the walk cycle. the knee joint misbehaves and does move out instead of along. When i try to move it back to where i want it then foot and lower leg just go nuts, like in a spasum. Any idea why it should do this. It seems to me that the leg always wants to be straight. When i try to bend it in anyway it goes nuts.

Sev

[SheepFactory]

if you are going to use a RP ik solver set it up all the way i say :)

-Create a locator

-Snap it to the knee bone , and move it a bit to the back

-Select the locator Than select the Ik handle

-Constraints -> Pole Vector constraint.

now the locator will control the twist attribute of the Ik. You can keyframe it along with the body to get rid of the knee twists etc.


hope this helps.

Ali

[SheepFactory]

By the way ,

did you set the preferred rotation angle before setting up the IK?

Legs look a bit straight judging from the image , if you didnt set the preferred rotation that might be the reason for its weird behaviour.

just a thought

A|i

[dedmann]

i agree with sheepfactory !

do exactly what he mentionned and your sure to have an ikhandle that works perfectly...always keep a little angle in your knee joint so that way your sure the ik will behave the right way and then like sheepfactory said constain a locator to joint of the knee(point constraint to be sure it centered)and then move it in front of the knee (locator) and by selecting it and the ik you do a polevector constraint that way by moving the locator afterwards the knee will follow the direction of the locator preventing all kinds of weird reaction when you do a walk cycle!

Dedmann

[Seven]

excellent, thanx alot guys. very helpful

[Seven]

This may sound like a VERY silly question, but how do i snap the Locator to the knee bone?

Ive used 3d max for years and have only just started to get to grips with Maya. Applying the principles I learnt in Max to Maya isnt working.

Its like learning it all over again :)

edit.. doing the 'selecting both the locator and the IK and pressing
Pole Vector constraint seems to solve my problem. However do I need to snap them together before hand?


edit2 :)... When I set the first key frame, move the legs, set the second key frame and run the animation. The legs look fine in the individual key frames but do a funky dance when getting from one key frame to the other. Im assuming this is wrong :)

At least the limbs arnt bending to the side any more :)

Anyone know of a really good noob tut for this.

[Mr Fudge]

Hold down "V" and then selct the locator and MMB drag it over the joint and it will snap to it's centre.

Holding X snaps to grid

Holding C snaps points on a curve etc.

- F

[DarkBane]

I don't know if this helps or not, but what the hell.

I used to have the same problem with the knees.

My instructor helped me with it.

When modelling, always have the limbs of the body a little limp. SO when your rigging the character the bones are slightly bent in the manner that they are naturally going to bend.

Then after you've laid out your bones. Use the "Channel Control" to restrict (for example) the knee from rotating on an axis that it wouldn't naturally rotate on. A knee can only bend in one direction, so make it do just that.

After thats done, set a Preffered Angle, and then you should be set.

Haven't had the problem since. I think it's a lot easier than having to deal with unnecessary locators and what not.

It takes up more time in the Rigging Process, but save so much time and trouble of having to troubleshoot it later.

Preparation is key.

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