Target bone won't let legs bend both ways in body turn.

[weaselbandit]

I have a problem with an animation I'm doing at the moment and was hoping some of you would be able to help me out.

I'm self taught with moho so there's probably a lot I don't know that would be able to fix this.
I've only recently started using target bones for the feet and now I'm not able to bend the legs both ways depending on which way my character is facing.

I have this stick figure that I would like to be able to do a full body turn with. I've created target bones for his feet but after I did that I am having a really hard time getting the knee to bend in both directions.
I've recorded a video of the problem here: https://www.youtube.com/watch?v=Yr-_3eMv8dk

Thanks in advance

[synthsin75]

Usually all you have to do is keyframe trying* to rotate the shin bone in the direct you want it to bend.


*It won't because of the target, but it helps Moho figure out what you're wanting.

[DK]

Hi Wes.
I've had trouble doing this as well. Set up a bone rig with targets on the feet and go to drop the body down and the legs flip in the wrong direction. My solution has always been to go back to frame zero and offset the angle of the offending bone a bit in the direction I want it to bend.




http://www.creativetvandmedia.com/Forum/LegBends.zip


It would be great to be able to change this behavior on the fly if anyone can think of a system that could do this? Maybe a smart bone rig?

Cheers
D.K

[synthsin75]

Hi Wes.
I've had trouble doing this as well. Set up a bone rig with targets on the feet and go to drop the body down and the legs flip in the wrong direction. My solution has always been to go back to frame zero and offset the angle of the offending bone a bit in the direction I want it to bend.




http://www.creativetvandmedia.com/Forum/LegBends.zip


It would be great to be able to change this behavior on the fly if anyone can think of a system that could do this? Maybe a smart bone rig?

Cheers
D.K

Hi David,

Yeah, just go to frame one (or where the leg starts to bend in the wrong direction), grab the shin bone with the transform bone tool, and rotate it to the left (or the direction you want it to bend).

If you ever need it to bend the other way, just set another rotation keyframe on the shin in that direction. It just tells Moho how to solve the bone rotations to reach the target. Moho usually just uses frame zero to decide this, but if the thigh and shin bones are in a straight enough line, it's kinda random until you keyframe a definite direction.

[DK]

Hey Wes. Thanks. That worked. Just one of those things that has always annoyed me. Took a bit of fiddling to get the shin bone to rotate though.

Cheers
D.K

[Greenlaw]

If you have trouble changing the IK direction by rotating the shin, try rotating the thigh bone instead. That may actually work more reliably. Rotate it only as far as necessary to make it 'pop' in the desired direction; if that doesn't happen, try rotating it in the opposite direction. After the 'pop' happens, you can minimize the 'pop' by animating the scale of the bone to 'straighten out' the leg. This can make the leg turn look much smoother.

(BTW, this method of changing IK direction is not uncommon when animating CGI rigs too.)

[DK]

Just out of curiosity...I tried adding a Smart Bone switch to aid in toggling the joint back and forth and for the life of me cannot get it to work. (I actually managed to crash Moho and that's when I stopped bothering)

Cheers
D.K

[synthsin75]

Controlling it with a smart bone will break the target anyway.