Cineversity

Hi

Is it possible to force a IK pose into FK, or vice versa?

I have a basic rig that has mocap animation data on, and wish to build on this rig adding IK and controllers.  I want to get the FK poses and force them to the IK or even the other way around, Im sure I can do this in MODO?

Thanks, Dan

Hi Dan,

You ask if that can be done in MODO? Perhaps check in the MODO forum about it.

Here, I can point to Bret’s tutorials about,
https://www.cineversity.com/vidplaytut/ikfk_arm_part_1a
Not sure if that is exactly what you are looking for.

Any IK works with a target and anything in the IK chain follows in a certain way. If you take the end point an comparable FK set up to move the same point of the IK, it might be not congruent to the IK result.

For that, you should have a look at the IK Tag. Help content:

IK/FK [0..100%]
Allows you to blend seamlessly between the chain’s current FK pose and the pose calculated for the chain by the IK solver.

Reset FK
Resets the FK state of each Joint to the IK state. This is useful if you have changed Joint positions or rotations in FK mode and want to reset them to their original (based on the IK) state.

My suggestion, create a new scene, use the Joint Tool and set up a simple “arm” with a 2D IK. Then use the Ik/FK slider to get familiar with the changes and how to go from one to the other method, without “jumps”.

All the best

Thanks for your reply.  I was referencing to MODO I wish to do this in C4D.  I wish to push the joints position from IK to the FK when I switch from IK to FK.  IK.FK Matching.

Thanks, Dan

Hi Dan,

Perhaps this series might help to get more clarity about the problem.
https://www.cineversity.com/vidplaylist/motion_capture_to_ik_retargeting_rig/

MODO, you might help me here by pointing out what function you have in mind:
https://help.thefoundry.co.uk/modo/
I can’t find any mentioning of a set up that allows for that, other than the initial set up procedure. Is it that what you had in mind.
Reading along the manual, it feels very similar to the set up that was introduced in r12 in C4D. “IK FK Blend” is how MODO calls it.

As I mentioned, the IK has its own idea how to solve a position based on the given set up, e.g., Goal and Pole.
https://help.maxon.net/us/#TCAIK-ID_CA_IK_TAG_SOLVER_GROUP
The update IK on FK will help a little but, but I guess not what you are after.

If you go to the main information about IK and how the IK Tags works:
https://help.maxon.net/us/#TCAIK-ID_TAGPROPERTIES

You will see that all the settings will be part of the final result, thus, those would be in need to be adapted to the new constellation that needs to be produced. To push the Joints from IK to FK instantly would require an adjust meant of goals and pols for example, with a decision of 2D or 3D solve as well. No idea, no suggestion for that, to have that push. Push, as I understand it means instantly.

My personal idea would be to move the IK close to the current FK, with a few frames to allow for a smooth Blend, so the IK/FK slider changes over time from one to the other. If rotations are large or have any more detailed attention is of course a question of any individual set up.

In a nut shell, this is how I understand your request:
https://vimeo.com/41570694

An example file is here:
Scene file
https://www.amazon.com/clouddrive/share/S5TgZlzH7EU2DITWpXat9A7ZUYoUPVMebd0bo5T0oug?ref_=cd_ph_share_link_copy
Note that FK is used from 0-30 then it blends just two frames, and 32 to 72 is IK used: even the keyframes on Joint.1 are given from 0-72, but at frame 30 they lose impact and at frame 32 they are ignored. IF the “Blend” time would be longer, a smoother transition would be easier to set up, as mentioned already.

If that is at all not what you are looking for, you might make a tutorial suggestion in the specific Forum, or if it is more a function that you miss, perhaps a suggestion directly to MAXON itself:
https://www.maxon.net/en-us/support/suggestions/

All the best

Thanks for your help and links I will check them now.  As to a reference to MODO having this feature its in a addon rigging kit.  Here is the feature in action.

https://www.autocharactersetup.com/animation-workflow/?rq=matching

Dan

Hi Dan,

I guess the best way would be to suggest this to MAXON directly:

https://www.maxon.net/en-us/support/suggestions/

All the best