View Full Version : Making goal stick to point

08-21-2013, 06:35 AM
This is a basic Ik for the leg. I'm having trouble with making the goal stay in place. I used Alt and drag and that works, but when animating it moves, making for jerky movement.



Ryan Roye
08-21-2013, 06:48 AM
This can occur when your leg's IK chains aren't closed. Try selecting the center of gravity, or the item just above the character's upper leg in the heiarchy and check the option "Unaffected by IK of Descendants" in Motion Options (m)

08-21-2013, 07:09 AM
I have the above the Leg bone unaffected, but still get those results.


08-21-2013, 07:36 AM
This is an effect of the softened IK in LW, the method prevents the old fashioned snapping that you used to get when a limb neared extension, but causes this "push away" effect near full extension instead. The things that fix it... proper amounts of prebend (a few degrees is usually fine), too much and the chain stiffens like this, giving "push", too much and chain extension slows down before the goal gets out of reach, causing "drift". Also, pop up the goal strength, and set one of the 2 bones in the IK chain to have stiffness 0.22 on the channel using IK. You can also work past it quite easily by making more bend in the bones than in the mesh... so full extension of the limb uses less than full extension of the bones, then clamp the rotations off at max.

08-21-2013, 11:43 AM
Changing the stiffness to 0.22 helped. It still wants to buckle. The legs are more straight and the bones are bended.


08-21-2013, 12:32 PM
Also dont use 2 channels on your IK like you have... keep it planar with a targeted plane item.

Ryan Roye
08-21-2013, 12:47 PM
Changing the stiffness to 0.22 helped. It still wants to buckle.

You can prevent the leg from snapping backward (OUCH!) by defining rotational limits if you haven't tried it already.

08-23-2013, 02:35 PM
Man! Thanks for this. I just got 11.5 and was having this problem. I LUV U ALL!