Fk-ik Snapping

[animationcl72]

Hey there

Well i just have a question and it might already be here but maybe i missed it. I wanted to see if anyone knew how to do a set up where you can switch from ik to fk seamlessly without blending. I have been looking at reels and it seems like a good idea for the animators. I have seen some pages where it shows a mel script but i want to know how to do it manually if you already have a FK and IK setup but wanted to do the switching without blend. If anyone could help me i would really appreciated it . Thank you!!

--OG

[molemansd7]

There's a lot that can go into a setup like that, so we can't get into all the details of it. However, one general technique to go from FK to IK, would be to copy your IK controller, parent it under your FK chain, and then match your control's position, rotation etc. to the duplicate copy. This will maintain the proper local transformations. Then, if you have one, you can snap the elbow controller to the WS position of the FK elbow. To go the other way, just query (using xform) the rotation values of the IK chain and apply it to the FK chain.

This gets trickier if you have attributes on one control that have to be taken into consideration as well. But that's the general idea of it all.

[joojaa]

QUOTE
it seems like a good idea for the animators.

Yes it does but in practice its not as cool as it sounds. See the thing your mathing across frames is momentum and when you switch form IK to FK you may want to have a frame in between This is where the possibility of blending the two interpolation types comes in.

So the problem is that its not very common for a animator to switch form IK to fk and then hold the solution still So the pure just switch as you are is less than ideal in practice. So while it is a nice feature and feels like the one one would want, it misses the mark a bit. So while the switch copying is sometimes ideal its not ideal to replace blending because what they regulary do is go key 2 frames in future to switch and then go back and adjust blend. So these 2 things are really separete tool set moves that benefit form staying so.

But yes it sounds cool but is relatively easy to implement form Ik to Fk and slightly trickier the other way around (you need to calc the plane of interest and position the pole vector on that plane)

So while you se a lot of ok IK(FK switchers you rarely see ik fk switching that does what one would ideal want, simply because people cant communicate the real need precisely. And here and now is easier to understand than 2 keys down the line