View Full Version : IK setting, please explain

04-15-2012, 01:05 AM
See attached JPEG:

Could someone explain what this dropdown menu's function is? The settings are:

Base on First Keyframe
Base on Most Recent Keyframe
Base on Current Time
Base on Frame ...

The explanation of this dropdown is seemingly missing from the dox. :devil:

04-15-2012, 01:16 AM
its for denoting where the IK solver looks to find its base/rest state/pose.

04-15-2012, 02:40 AM
Thanks for the info.

I don't understand the implications, but that's more than the PDFs seemingly had.

04-15-2012, 04:53 AM
IK uses a base state/pose (vis a vis prebend) to determine how the chain should behave, right... this setting tells the solver which frame to look at to get that pose.

04-15-2012, 05:07 AM
So I suppose itīs useful when you have a model with not bent arms/legs/whatever. Then could you rig a character at frame 0 (in instance) an then pose it with arms,legs... bent in frame 1 and specify the base current time on 1? Should it works this way?


04-15-2012, 05:11 AM
Yes... if for some reason you needed to setup a character with perfectly straight limbs at bind pose, you could key the prebend on another frame and reference that... that's basically the purpose of it, whilst things like current/most recent frame options allow you to alter the IK behviour across the course of an animation by changing FK values on the items in question.

04-15-2012, 09:32 AM
Ahhhhh, "prebend"! That makes a lot of sense. Be nice if the manual mentioned it, at all.

"Bind pose"-- is that a common term of art amongst riggers?

Thanks, RH!

04-15-2012, 10:48 AM
RebelHill recommended to me the Thimoty Albee book about character animation and he talks about that issue. Very interesting... a few improvements in setup (joints, same as item motion controllers, etc) since Lw8 so the book could be a bit out of date, but the basics still works