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IK Constraints

Posted: Sat May 03, 2003 9:58 am
by DMBadCat
could somebody explain the functions of these things? I don't know about IK contraints, and they sound pretty useful...

Posted: Sat May 03, 2003 10:17 pm
by DMBadCat

Posted: Sun May 04, 2003 1:54 am
by Hos
IK means 'Inverse Kinematic'.

I would go searching for IK/constraint tutes at the Elysiun site.
(This forum was intended more for development.)


Posted: Mon May 12, 2003 11:54 am
by Guest
FK = Forward Kinematics
IK= Inverse Kinematics

The idea is that with forward kinematics you rotate and
parent objects to get poses you want..

With IK you create a end effector chain that determines
the rotations necessary to orient objects into a pose.

Your typical human body contains 70+ joints not including your
vertebrase in your neck and the others that allow you to move..
Without IK if you have to move each joint it would take you
forever, with IK, you only need to move fingers, wrists, feet,
and maybe a few extra end effectors to control knees and elbows,
the neck.. But its so much easier than what you would have to do.

Its questionable if its become easier in Blender, I read the
docs on OOM, and realized the artist avoided using character animation, which is a major weak spot of blender.. IT needs work..

how it works

Posted: Wed May 14, 2003 8:32 pm
by solmax
- make three bones and orient them like a leg plus foot. make sure the knee is not completely stretched (angle less then 180 deg).

- press TAB to leave EDIT mode.

- create an Empty and remember its exact Object name (like "Empty" or "Empty.001"). move it to the joint where the foot starts (ankle).

- select your armature(bones)

- press CTRL + TAB (pose mode). now you can't edit length of the bones by moving around the joints, but rather move and rotate thebones themselves. anyway leave everything as it is ( as with "real" bones).

- rightclick the foot bone to select it and then goto CONSTRAINT buttons (the one with the chain symbol)

- Click ADD and choose "IK Solver". In the OBJECT field type in the name of your Empty. Click CTRL + TAB again to leave EDIT mode.

-Voila - you can move around the Empty and the bones rotate automatically.

hope that helps

Posted: Thu May 15, 2003 12:31 am
by DMBadCat
Cool! Now I can do even more, with a LOT less work! thanks a million :P

Posted: Fri Jun 27, 2003 1:39 am
by luckybreak
on the topic of contstaints are the any plans to provide a scale constraint to go along with the location and rotation ones - not really for armatures. But very handy for objects

Youtube video helped me with ik constraints

Posted: Wed Jan 23, 2013 7:41 pm
by shaun.bc

Posted: Wed Jan 23, 2013 9:12 pm
by Tehrasha
Wow.... on topic necro post. :)


Posted: Thu Jan 24, 2013 8:11 am
by shaun.bc
Yeah, wasn't really paying attention to the date of the posts. :oops: