View Full Version : what is the method you use for a spine

06 June 2003, 02:50 AM
what is the method you use for rigging a spine
FK or IK Spline or anything else ?
thanks for any advise

06 June 2003, 01:26 AM
Hey xteapot,

You should really look into getting Jason Schleifer's DVD on integrating a creature rig into your pipeline.

Its got a really awesome spine setup that has an IK spline setup, a FK setup and a stretch setup. As well as some cool little warning colors on the spine:) :bowdown:

If you cant afford it or just could'nt be bothered, then I guess the general method used is to setup an IK spline back with clusters that are then point and orient constrained to null nodes which are parented under a chest and hip control.

This is pretty much the most basic method that is used.

Try to get about 4-6 clusters out of your back, so you get a little bit more of a nice curved bend.:thumbsup:
Hope this helps!


06 June 2003, 02:18 AM
thanks loked

I really want to buy every learning DVD
but it's hard to get it here it Thailand
if I want both spline IK, FK and strecth spine
it's mean I need 4 set of joints ?
one for a real joint to bind skin
and three for spline IK, FK and strecth spine
and do constraints and expressions to combind it
am I right ?


06 June 2003, 03:07 AM
Well, actually the FK method is'nt entirely FK on all the joints that you have in the ikspline. You also dont need so many seperate skeletons. The stretch works within the IK skeleton.

Basically what you do for the FK is you create a 4 joint chain that goes from the starting joint of your ikspline to the ending joint of it. You then parent the chest control and under the top joint in this 4 joint chain and the hip joint to the bottom one. This way when you rotate the FK system, your hip and chest controller move with it. Hope you understand this, its a bit brief, but its really not that complex to setup.

For the stretch, you cant use Jason's method, because it requires you to have certain scripts and its pretty complex. You'd need the DVD for this. Basically what he does is get the length of the ik spline curve and based on its distance, the joints scale in Y. (Something along those lines) However, there is a simpler version of it that I sometimes setup. I basically just setup an attribute on one of my controls that is connected via an expression to the scale of the y in the IK spline joints. This is nowhere near as effective as Jason's method, but it does get a reasonable stretch in the spine area. I then just animate that attribute accordingly.

If anybody else would like to explain Jason's stretch method in a little more depth please feel free, but I'm not trying to tackle that one.

Hope you got all of that. The only seperate skeleton chain that you will have is the 4 joint FK one that controls the hip and chest controls. The other one, should be your bind one with the ik connected and the expression controlling the scale of those joints.

Good Luck!!:thumbsup:

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