ik setup for long neck and head

[Stray]

Hey srt,

I have a method (actually 2) that can handle a long neck of a flightless bird. Currently though the methods are incorporated into my CA system I am developing.

If you wanna come on as a demo artist I would be happy to hook you up.

Something to think about...

-Stray

[LucentDreams]

best bet for such a long and flexible area is spline IK, you chould check out naams bones to spline expression, don't know how I lived without that expression, add on B rotation expression that averages the rotation of the first and last bone on the chain throughout the rest of the chain and you have an extremely flecible yet easy to control neck.

[srt]

Originally posted by Kaiskai
best bet for such a long and flexible area is spline IK, you chould check out naams bones to spline expression, don't know how I lived without that expression, add on B rotation expression that averages the rotation of the first and last bone on the chain throughout the rest of the chain and you have an extremely flecible yet easy to control neck.

this one? (http://www.xs4all.nl/~naam/goodies/bonestospline.txt)
you just animate the spline and the bones follow?

i just noticed i have an align to spline tool from fabian as well. got it with the muscle bone tool but haven't played with it yet. anyone have any experience with fabian's tool?

i don't have time to try either of them right now...soon i hope. thanks kaiskai.

stray, i am not sure what it means to be a demo artist. if you are looking for extreme novices to test your stuff i would be interested but i don't have alot of time to devote to it. this is an evening/weekend hobby for me.

[LucentDreams]

expression has the same name as I specified no?
Yep it is the one, there are to plugins out there (fabians being one) that seem similar at first, but suffer from one severe flaw, only one bone per point on the spline, where NAAM's expression does as many bones between two points as you want. Meaning a long neck like yours can have two controllers yet be capable of every type of curve you can think of.

[Stray]

Yeah,
that NAAM expression is great. I cannot get the bank rotation thing working though.

Also it is the bone lengths are constrained to the length of the spline. you have to put some sort of constraint on it so that it doesn't stretch too far out of a beleivable range of movement.

Kai that would be great if you could post an example scene of what it is that you are talking about that would be great.

My system is basically a part of the FK spine system that I devised. It is really stable and will give you a wide range of movement and contol. It has a bank interpolation on it as well.

About the demo animation stuff. Basically the agreement would be that you would own your model (natch!) and you would get a chance to use the CA tools for free. the only stipulation is that you let us use your animation for promotional purposes. (Pretty much a movie over at the portal).

As for the leg control I have 2 options . one is a 3 bone system taht I devised and the other is a revised version of my reverse foot setup..

either are sufficient for the leg type your creature has..

-Stray

[LucentDreams]

Originally posted by Stray
Also it is the bone lengths are constrained to the length of the spline. you have to put some sort of constraint on it so that it doesn't stretch too far out of a beleivable range of movement.

Kai that would be great if you could post an example scene of what it is that you are talking about that would be great.

My system is basically a part of the FK spine system that I devised. It is really stable and will give you a wide range of movement and contol. It has a bank interpolation on it as well.
-Stray

My setups basically uses a bank interpolation I guess probably simiar to yours. As for constraining the length, I feel one of its advantages is the ability to stretch. What I do instead is set an colour expression on it that indicates to me when the spline has reached a specified length (that I figure out by simply stretching to what I feel is a believeable limit and looking at ths splines length.) if the splines is longer then that length, the bones change colour. This is how I've been setting up all areas one would typically limit, I hate limits as they do just that, they limit you. instead colour indicators tell you when you are passing limits so you can avoid doing so, but when you do need to break a limit its still possible to do so.

last I have a null connected using expresso, to each of the points on the spline so I don't have to go into point mode to animate the spline which is tedious and bad workflow. Only challenge I"ve run into this is controlling the spline tangents, only solution I have is a coffee node since regular nodes don't have access to spoline point tangents. the node isn't the most ideal setup compared to mayas spline IK, but it does work, just means I have a seperate null for the tangent then I do for the point itself and just child the tangent null to the point null.

[srt]

i have been playing with naam's bones to spline expression for a while now and it seems to promise the most control and versatility of any other method i have tried for controlling the neck.

based on your last post, kaiskai, i assume i should be using a bezier spline with only two points and controlling the arc of the neck with the tangents?

would you mind sharing your expressions for adjusting bone color based on the length of the spline and for controlling the tangets?

steve

[Cactus Dan]

Howdy Steve,

I don't know if you've found a workable IK solution yet for the long neck of your flightless bird, but I though you might be interested in this:
http://home.earthlink.net/~cactusdanl/LongNeck.mov

It's using a Spline IK Expression that will be a part of the IK Tools plug-in I'm currently developing.

In the sample movie, the head is set up with my Foot IK Expression and the neck is set up with my Spline IK Expression. The only thing animated is the Head Controller object.

Adios,
Cactus Dan

[flingster]

this thread is making interesting reading...and being a complete noob at all rigging...can i ask a simple question and probably rather dumb question but here goes...your patience is appreciated.

but if you currently use any of those methods mentioned...as far as i can tell...you lay say 5 bones along a spline...but they are all uniform lengths...would it be useful to scale the bone lengths...so
bone 1 would be say longer in length than bone 5...this way if scale/length is dropping as they are aligned on the spline...when it comes to animating it...you could have your stiff rigid attachment at the neck to body eg bone 1 longer and less mobile...and bone 5 shorted yet more mobile (neck to head)...more whip like in its movement.
does this make sense? am i totally missing the point?
cheers

[Cactus Dan]

Howdy,

Originally posted by flingster
but if you currently use any of those methods mentioned...as far as i can tell...you lay say 5 bones along a spline...but they are all uniform lengths...would it be useful to scale the bone lengths...so
bone 1 would be say longer in length than bone 5...this way if scale/length is dropping as they are aligned on the spline...when it comes to animating it...you could have your stiff rigid attachment at the neck to body eg bone 1 longer and less mobile...and bone 5 shorted yet more mobile (neck to head)...more whip like in its movement.
does this make sense? am i totally missing the point?
cheers

I'd say you hit the nail on the head. The sample movie I did was a quick test in answer to another thread to see if it would work. After posting the sample, I played around with the rig some more and came to the same conclusion that it works better when the bone lengths are set so that they gradually get smaller toward the end of the chain (just as you suggested).

Adios,
Cactus Dan

[flingster]

oooh cool...was kinda curious but my knowledge of all things moving is pretty limited to say the least! cheers for that.
:thumbsup:

[srt]

that looks like just the thing i need, cactus dan. unfortunately, i am using xl8.2 and your plug only works with 8.5, right?

steve

[Cactus Dan]

Howdy,

Originally posted by srt
that looks like just the thing i need, cactus dan. unfortunately, i am using xl8.2 and your plug only works with 8.5, right?

steve

Unfortunately yes. It only works with 8.5.

Adios,
Cactus Dan

[CGTalk Moderation]

This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.