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ukyo
03-06-2005, 02:06 AM
is it possible to have an FK/IK leg switch if so how.woiuld it be similar to a arm set up, and how would that affect a reverse foot setup?

M.E.L.
03-06-2005, 02:32 AM
You wouldn't necessarily want a 'switch' so to speak.

Just create a custom attribute on your foot control object called IkBlend or whatever, then connect the ikHandles ikBlend attribute to it and voila...blending IK/FK leg :thumbsup:

-shawn

thematt
03-06-2005, 08:51 AM
i don't know but i really hate maya own Ik/Fk blending because you have a snap from IK->Fk but not FK->IK and that's very annoying..My POV.
cheers

M.E.L.
03-06-2005, 05:16 PM
Well, Maya's FK/IK stuff is brutal with it's snapping, which I why I dug around and found the technique that I posted up before, there's no snap at all going from IK->FK and vice versa...it's a straightforward blend back and forth.

ukyo
03-06-2005, 05:43 PM
thats really cool thanx, but is it proper. im not really a rigger im just an simple modeler animator who would sell his mother for a good rigger. i love you guys ive been using final rig and package man to animate, they r the nicest riggs ive used so far but the each have things i wish i could incoprate into one rig. to make a long story longer they have some kind of triple arm ting set up and there ik/fk blend switches the joint system back anf forth. does it matter or is it ok to use the fk/ik blend like u described earlier?

john_homer
03-06-2005, 06:13 PM
You wouldn't necessarily want a 'switch' so to speak.

Just create a custom attribute on your foot control object called IkBlend or whatever, then connect the ikHandles ikBlend attribute to it and voila...blending IK/FK leg :thumbsup:

-shawn

I used to do that... untill it got tested by the animation director here.. with disasterious results!
it basically doesnt work if you are blending from 2 quite different poses, because you are essentially blending from joint rotations to ik positions.
try this, set it to ik, and drag the foot back quite a bit, now try and blend it to an Fk position of the foot out in front.
the ball joint will do some funky flips and wiggles ;(
this technique is fine if the animators are blending to/from similar positions, it just depends if you want to limit them.
I choose to rewrite my autoRigger to use the old (but reliable) 3 skeleton rig as sooon as I discovered this.. well after a bunch of testing to confirm... there are ways of getting it to work, but they require training the animators to set extra keys, which is more work for them.. and just clunky workflow...
the tripple skele works perfect every time, but is a lot more setUp... so script it ;)

.j

M.E.L.
03-06-2005, 06:15 PM
I've been incorporating the ik/fk blend I described into my rigs for about 3 years now, works like a charm and avoids the big hassle of the triple chain stuff :)

simple rule of thumb with rigging is K.I.S.S, Keep It Simple Stupid :thumbsup:

john: by chance were you still using the ik on the ball of the foot and toe's? I've run into this before which is why I string in an extra control node for the blending off of the foot IK as well (I've seen that flip and wiggle like you mentioned and ran across it when first using this trick).

-shawn

p.s. you might want to keep your mother and just post up here askin any rigging q's ;)

john_homer
03-06-2005, 07:04 PM
john: by chance were you still using the ik on the ball of the foot and toe's? I've run into this before which is why I string in an extra control node for the blending off of the foot IK as well (I've seen that flip and wiggle like you mentioned and ran across it when first using this trick).

yep, blended them off... and still had a problem... I would be interested in seeing your solution if thats possible??


p.s. you might want to keep your mother and just post up here askin any rigging q's ;)

what?? thats makes no sence...

.j

M.E.L.
03-06-2005, 07:13 PM
what?? thats makes no sence...

.j

that was in response to


thats really cool thanx, but is it proper. im not really a rigger im just an simple modeler animator who would sell his mother for a good rigger.

john_homer
03-06-2005, 07:21 PM
oh, ok... sorry.
I though it was odd that you started talking about my mother:rolleyes:

thought I must have really offended you...

do you have an example of your leg?
I would love to see one I can't break ;)

.j

M.E.L.
03-06-2005, 07:24 PM
oh, ok... sorry.
I though it was odd that you started talking about my mother:rolleyes:

thought I must have really offended you...

do you have an example of your leg?
I would love to see one I can't break ;)

.j

haha, no need to apologize man, it's cool :) I'm not one to talk about mothers like that.

You didn't offend me at all, check your PM's...I'll send you the script if you like. Be cool to get some more opinions on it and stuff :)

-shawn

john_homer
03-06-2005, 09:31 PM
hay ukyo,

shaun and I took it outside and did some tests, and found that it does flip and wiggle a little... works great for arms though , and he's never met my mother ;^)

so for the leg you may want to go with the tripple skeleton rig.

have fun

.j

ukyo
03-06-2005, 09:35 PM
hhahaa this post has been both informative and fun!!

ok i understand setting up a triple arm setup but how would that work with a reverse foot setup since the reverse foot joints are not conected to the joint chain. im sorry if this is a stupid question but thats why mom is on the auction block shaking in her boots http://www.cgtalk.com/images/icons/icon10.gif. or would the setup simple allow for the entire leg to become fk all the way to the toes and then the ik leg would be the one that has the reverse foot? did that make sense?

M.E.L.
03-06-2005, 09:41 PM
shaun and I took it outside and did some tests, and found that it does flip and wiggle a little... works great for arms though , and he's never met my mother ;^)


agreed...john took the setup out back and beat the hell out of it :P For the record, John is correct, I have never met his mother :)

ok i understand setting up a triple arm setup but how would that work with a reverse foot setup since the reverse foot joints are not conected to the joint chain.

hmmmm...now you're tapping some old old thoughts there, it's been quite sometime since using a reverse foot...always done the multiple ik chain setup. John, you wanna handle this one?

I would assume that with a reverse setup type leg you would quite simply require the usual leg bones (hip, knee & foot).

-shawn

sneezy
03-06-2005, 10:53 PM
I think what you want to do is treat the 3rd averaged leg as *the* leg skeleton for whatever tutorial you are using to hook your reverse foot into the rest of your rig.

john_homer
03-06-2005, 11:02 PM
sorry, I'm just too busy for details..I've spent too much time here already...

make leg joints, hip, knee, foot, toes.

duplicate 3 times.

rig 1 with reverse foot.
have 2 as FK.
drive 3 with 1&2.

.j

mental
03-06-2005, 11:37 PM
ok i understand setting up a triple arm setup but how would that work with a reverse foot setup since the reverse foot joints are not conected to the joint chain.
hmm, i'm not so sure that you do understand the triple arm setup. to elaborate on the method John mentioned:

Goosh wrote this helpful >tutorial< (http://student.vfs.com/%7Em07goosh/Tutorials/ikfkswitching/ikfkswitching.htm) on constructing an IK/FK arm which may be modified to work for your situation.

thematt
03-07-2005, 06:40 PM
Well, Maya's FK/IK stuff is brutal with it's snapping, which I why I dug around and found the technique that I posted up before, there's no snap at all going from IK->FK and vice versa...it's a straightforward blend back and forth.



mmm..not sure about that..so to speak you setup Key on you're fk, roatating leg, setup up keys everything's fine so far..then you want to use the IK..but you're leg is far away and in FK..you say cool just make a sanp IK to FK with maya own IK/FK snap, so you keep on animating..I aniamate with my IK and I like it blablabla..but after a while I need to go back to my good old FK, how do I keep on to that point?.
Because maya has no FK to IK Snap, so I have to blend back to the position of my old Fk..and that's not something I want..so how do you do with your setup.
Sorry if I'm being dumb :(..but i don't really get it.

thanks for the clarification

You can send me your script too I'm curious about it now :)

cheers

Andrei2k
03-10-2005, 09:57 PM
Yes I have been wondering the same thing thematt just mentioned for a while. Is there something I'm missing or a crazy workaround?

thematt
03-11-2005, 12:34 PM
Shawn are you still up for a little bit of explanation..pliiiiiiiiiizzzzzzzzzzz :)

M.E.L.
03-11-2005, 04:43 PM
Shawn are you still up for a little bit of explanation..pliiiiiiiiiizzzzzzzzzzz :)

Heh, sure thing matt :) Sorry it's taken so long, production sped up a bit this week.

Basically how the blend works is that you ramp the IK off, add in your motion to the arm or whichever and then blend back to the IK (the reason for the blend that I created in the script was that the animators I worked with only used FK to tweak movements and arcs so the animation would go IK Pose -> Ik Pose and then the FK inbetween).

In general it works like this:

Ik Pose 1 = ikBlend 1
|
Fk motion = ikBlend 0
|
Ik Pose 2 = ikBlend 1

Now what happens is as the ikBlend is ramped back on, the solver begins to move towards it's next key and the FK begins to blend onto it's solver. Basically, what I meant by the 'snap' is that the default Maya Ik/Fk stuff is 0-1 values...you set it to FK, set your keys..go to set it back to IK and it just snaps into position...you don't want that, you want a nice smooth blend between the two to make nice arcs.

I'll post a test scene up that you can mess around with, it may take a bit though as I'm a little busy at the moment.

-shawn

JFFORTIN
03-11-2005, 10:13 PM
One other thing u can come across is like for arms exemple when u blend ur ik anf fk arms and there are in extrem pose , when u blend they will twist twist like crazy its because the rotation value is probably going form negative to positive value ....and the solution is to use aim constraint to blend ur ik anf fk arm............no gimbal lock at all when your arm will blend .....so both arm can have crazy value and will always go in a straight line the only problem is ur arm wont do a arc when they blend but will go in a straigh line.... but who will see tha :P
have fun with your Rig

thematt
03-13-2005, 11:18 AM
mmm..ok so I guess it's really base on animator workflow..I suposed this way it works, but I incountered a bunch of animator that wanted snap from Ik to Fk and Fk to IK, I guess if you can do why not..thanks for the info then I wil tech my animator your workflow so maybe it ease the production..and my work as a TD..pfffffff..;)

cheers

if I can take a look at your scene i'll be cool.thanks anyway.

ukyo
03-13-2005, 04:11 PM
you rigging people really amaze me, god i love you guys!

protproto
03-13-2005, 10:45 PM
sorry for my post, I deleted it, as I must have misunderstood a lot in the conversation.

maia

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