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View Full Version : FK/IK_Spine discussion

Tak Tak
06-28-2006, 06:47 PM
Hi,

I'm now trying to find good way to create IK/FK_Spine system which is nice and easy to animate. Here is my first test of my IK/FK_Spine system. There is simple 3 skeleton chain for FK(green) and Isner spine for IK(red) Yellow cubes are for enveloping only. Between green and red there is simple IK/FK blend with pose/position constraint.

Biggest problem with this is when you bend FK chain to tight angle, Isner spine woun't bend as much as it should(because of it's structure). Another problem is missing of stretch and squash system.

I just wonder if you have some nicer way to create IK/FK_Spine. If you do, please join to this discussion and share your way to solve problem. I'm using XSI, but I want it to be software free discussion so...

Download TEST 1(TechSmith Codec) (http://www.kolumbus.fi/d_loosers/3d/TEMP/IKFK_Spine_TEST.avi)

Thanks
eek
06-28-2006, 07:26 PM
The issues I have with fk/ik spines is essentially drifting of the two rigs, and additionally the compound effect of addtive rotations. Its generally why ive stuck with my semi-fk/ik spine. It allows to drive it in fk, and ik at the same time, essentially a simplfied Isner. On top I have main controls essentially fk. Its worked for 40+ rigs so cant be bad.
PEN
06-28-2006, 08:48 PM
I have more of what Charles is talking about. I have also done a true IK/FK spine as well much like you would do an arm where there is the IK, the FK and the constrained joints so you end up with three changes and blend from one to the other. That resolves the problem that you are seeing. The other way is oposite of what you have. Have the IK drive the FK and the FK walk off the ik when in use.
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06-28-2006, 08:48 PM
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