# Is mixed FK/IK possible?

• Many times I get stumped with FK/IK, because in some parts of an animation I want the hands or feet to flow naturally when they are not attached to anything, therefore using FK, while in other parts I the hands and feet are attached to something, so want the precise control provided by IK.

I could never develop a generic approach to mixing these modes, because the FK/IK setting cannot be animated; it's either the whole animation one, or the whole animation the other.

Anyone has developed a general approach to preparing animation segments where hands alternately get constrained or free?

Also, you guys think it's feasible for SM to have that setting animated? I'm not sure of the maths involved with IK, but can't be too easy.

Finally, you guys think it's feasible for SM to have that setting not only animated, but also fractional? Like, a setting of 0.7 means the hand position/rotation is given by 0.7 of the coordinates calculated via FK + 0.3 of the position/rotation set via XYZ/rotXYZ dials? That is, to smooth a transition from FK to IK and then back to FK?

• @fbs7

Have you considered constraints? They can not only be animated ON/OFF, but it can also be fractional 0-1.
Otherwise animating in Poser is almost a constant on/of toggling of the IK. Even a simple walk needs to be animated with both IK & FK to make it look right, otherwise it will look like a lot of the Maya stuff out there: feet nailed to the floor, and hip moving without any weight.

Most likely you figured this out already, but when you turn off the IK, the feet/hands seem to get all wacky if posed incorrectly (wrong rotational values). To avoid this, it's best to turn off Use Limits before turning off IK. Just don't forget to turn Use Limits back on.