View Full Version : spine needs help!

08 August 2005, 01:31 AM
So i have a little problem, infact, i have no idea how to do this ..... ok so this is a robot and it's spine is located by the nice little white circle i made :) that part is skinned to the tube and is stretchy. i was told not to use any IK for it, but it certainly doesn't have the control than, let's say the Hogan rig does. how does the Hogan rig use controls that rotate so nicely? i am starting to think the joints arent laid out properly b/c when i rotate the spine tube, the chest, shoulders and head don't move also. any suggestions would be GREATLY appreciated .....

08 August 2005, 07:27 AM
ok so i figured this out for the most part.

i'm still wondering how to parent joints to controls, when i have already parented the geometry to the joints. Does anyone have any ideas? not parent constraint right?

08 August 2005, 09:49 PM
its best to group the controling object first ( and centre the pivot too ) make the joint the parent of the group..

use point and orient constraints to control the bone from the controlling object..

Another way of doing this is to do away with controlling objects alltogether.. and under the bone attribute turn on the handle, and offset it so its easy to select..

08 August 2005, 01:08 AM
hmmm i couldn't get it to work. are you saying the controller should be the grouped with the joints? i made the control into a group, and then parented it to the joints and constrained but nothing worked, i mean, it didn't really make much sense to me. is this way to rig smooth bind common? it works fine but maybe for productivity it might not be?

08 August 2005, 02:13 AM
hmmmm.. what i mean is.. if you group the Control ( Ctrl - g )
so you get a group.. with the control sitting under it as the child..

with this you then make the bone the parent (constaint) of the newly created group (not the child )

then you can control the bone with a constraint coming out of the child ( controller )

look ( at this file.. it'll be easier to understand

08 August 2005, 03:08 AM
ahhh ic - i understood the first part but i see that you parent constrained it. the parent constrain would break on me all the time, prob b/c it wasn't in a group. thanks for clearing that up for me! :)

what's the best way to rig a neck? i always have animation that looks mechanical. i wouldn't use any IK would i?

08 August 2005, 04:33 AM
ahh.. yes the neck is interesting.. i think it consists of 6 or so vertabre.. the neck will tilt from side to side and front to back.. however it really dosent twist at all.. all axial rotation ( y axis in maya) is done with whats called the atlas bone at the base of the skull...

you can do this setup with a couple of bones which gives a simple control..
have a look ( at this one..

this has about 5 bones.. setup with spineIK.. and the spline curve is in turn smooth bound to two extra bones.. at the base of the neck and the top.. you'll see that the top bone ( with the handle ) y rotation also controls the very top bone ( atlas...) this is one way of doing it realistically..

a little more setup on this. and it would work quite nice...

08 August 2005, 06:28 AM
wow i've never seen a neck done that way. that's really cool ..... thanks! :) i'm definitely going to use that in my rig. i guess that's the way ik spline is good for? to bind to other joints so it's manuverable? i've seen it being used for spines also. have you seen it used in other parts of humans?

08 August 2005, 10:37 PM
well in the human body it best suit the spine and neck.. you can use it anywhere really.. but is best for multi chain bone structures.. the beauty of the spine IK is that its controlling object is a spline.. and you can run soft body on this object.. set up deformers.. even use wires.. so you can animate this in almost anyway you can think of...

if you create a bone chain on a circle spline for instance you can offset in the IK handle.. and the bone chain will track the circle perfectly..

anyhow! glad you liked the head and neck setup!

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