Posing by hand: IK, FK and hands

Studio’s default animations rarely land exactly where you want a shot. Hand-posing with the IK and FK node handles is how you fix that, whether it’s straightening an elbow, planting a foot, or curling a fist. The two systems work very differently, and knowing when to reach for each one saves you a lot of fighting with the rig.

1. Pick IK for big moves, FK for fine control

IK (inverse kinematics) gives you a single handle at the hand or foot. Drag it and the whole limb bends to follow, the way a real arm or leg would. It’s the fast way to do gross posing: plant a foot on a step, reach a hand toward a prop, set the overall silhouette.

FK (forward kinematics) puts a handle on every individual bone, so you rotate the shoulder, then the elbow, then the wrist, one joint at a time. It’s slower but far more precise, and it’s the only way to get natural-looking bends in a chain like the spine or fingers, where IK’s single end handle can’t express it.

You don’t pick one for the whole character. IK and FK are toggled per limb in the Anim pose panel: select the character, open the Anim tab, and switch each limb group (arms, legs, hands) between IK and FK independently. A common combination is IK for the legs to keep feet planted, FK for the arms to fine-tune the elbow bend.

2. Select nodes without fighting the rig

Hold Ctrl and click to select multiple nodes at once, so you can move or keyframe several of them together instead of one at a time.

Dragging directly on a node rotates it. If you only want to nudge a selection’s position without triggering that rotation, hold the mouse pointer slightly off the node itself while you drag, rather than right on top of it.

3. Shrink and declutter the node markers

Default node markers are large, and on a crowded rig, or on small items like rope or jewelry, they overlap and make precise clicking hard. Two fixes:

• Go to System > Options > Axis Settings and lower the Size value to shrink every node handle.
• Set the node Display Type to Selected, so only the currently selected object’s nodes are drawn. This alone removes most of the clutter from other characters and items sharing the scene.

4. Pose fists and hands

Fingers are the one place where FK per-bone posing gets tedious fast, so Studio gives hands their own shortcut. Open the Animation > Hands menu to open and close a fist as a whole, or apply one of the built-in hand pose presets instead of rotating each finger joint by hand.

For the whole-fist presets to take effect, turn FK off on that hand. Animation > Hands drives the fist and its presets directly, so leaving FK enabled on the same hand fights it with per-finger control and the preset won’t apply cleanly.

Fixing the ankle-spin glitch

Occasionally a foot or ankle starts spinning uncontrollably when you try to adjust it, usually after switching IK/FK states or loading a pose onto a rig that’s already mid-animation. This is a rig desync, not a broken pose.

Click a vanilla or default pose to reset the rig first, then reapply the pose you were building. That clears whatever bad rotation state the ankle got stuck in, and your pose reapplies cleanly on top of the reset rig.

Save a full hand-built pose as one Timeline keyframe

If you’ve hand-posed several limbs with IK and want to lock the whole result in as a single Timeline keyframe, select every relevant IK node before you keyframe, not just one. Expand any folders in the node list so nested nodes are included in the selection, then keyframe the whole group together. Keyframing nodes one at a time leaves gaps where limbs you touched later aren’t captured in earlier frames, which shows up as things snapping into place partway through playback.

See animating with Timeline for the keyframe workflow itself.

Advanced: hijacking specific bones

Normally, adjusting IK or FK on a bone overrides the base animation for that bone across its whole length. Hijacking is the technique of choosing exactly which bones follow your manual edit and which keep following the original animation, so you can, for example, adjust just the hands on a mocap animation while everything else keeps playing as authored. This is done through HS2PE’s Advanced IK panel, which exposes per-bone control over what drives each one. It’s a deeper technique worth knowing exists, but treat it as a follow-up once you’re comfortable with basic IK/FK posing.

Quick reference

For locking a hand or prop to a moving target once it’s posed, see node constraints. Facial posing follows a similar hands-on logic through sliders instead of nodes, covered in blend shapes.