Beginner Mistakes in 3D Timing and Motion: Diagnosis and Corrections

1) Symptom-to-cause mapping: what you see vs. what’s actually wrong

This chapter is a troubleshooting guide: start from the visible symptom, identify the most likely underlying cause, then apply a focused correction. The goal is to avoid “random tweaking” and instead make one change that predictably improves the shot.

Quick triage order (saves time)

• First: check contacts and constraints (a sliding foot can masquerade as “bad timing”).
• Second: check for pops (a single tangent spike can ruin an otherwise good shot).
• Third: reduce jitter/over-keys (noise hides the real motion).
• Last: refine holds and add contrast (polish after stability).

2) Targeted corrections in the graph and viewport

Each fix below is intentionally narrow: apply it, re-playblast, and only then decide whether you need another pass.

A) Robotic motion

Typical pattern: many keys, evenly spaced, with similar ease-in/ease-out everywhere.

Fix 1: Reduce keys (keep intent, remove redundancy)

1. In the viewport, identify the few controls that define the action (often: root/COG, chest, head, planted limb controls).
2. In the graph editor, box-select a section and run a key reducer (or manually delete every other key) while watching the curve shape.
3. After deleting, scrub: if the pose drifts off-model, add back a single breakdown rather than re-keying every frame.

Rule of thumb: if removing a key doesn’t change the silhouette or contact, it probably wasn’t helping.

Fix 2: Create contrast by reshaping one curve at a time

1. Pick one driver curve (often COG.translateY or COG.translateZ).
2. Make the “decision” portion of the move clearer by tightening spacing: pull tangents so the curve changes faster in the intended burst and slower elsewhere.
3. Replay at speed. If it improves, repeat for the next most important control.

B) Floatiness

Typical pattern: drifting contacts, overly smooth vertical curves, and no clear settle.

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Fix 1: Lock contacts (stop the drift first)

1. Identify the contact phase (foot plant, hand on table, etc.).
2. In the viewport, pin the contact: use your rig’s space switch/constraint (e.g., foot to world, hand to prop) or an IK pin.
3. Match transforms on the switch frame (so there’s no pop), then keep the contact stable for the duration.
4. Verify by scrubbing: the contact point should remain fixed in world space.

Fix 2: Re-time the settle (make the stop feel supported)

1. Find the frame where the body should be “supported” (the moment weight is clearly on the planted limb).
2. Move the COG/root keys so the settle happens sooner than your instinct if it feels floaty (floatiness often comes from settling too late).
3. In the graph, reduce lingering motion: shorten the tail of the curve after contact and avoid long, gentle eases that keep drifting.

C) Snapping / popping

Typical pattern: a single-frame jump in position/rotation, often caused by tangents, interpolation, or switching.

Fix 1: Fix tangent overshoot (the “spike”)

1. In the graph editor, frame the problematic curve and locate the spike near the pop frame.
2. Set the key’s tangents to a safer mode (e.g., clamped or auto), then manually flatten/adjust if needed.
3. Check neighboring curves too (a pop in the wrist might be driven by elbow or shoulder rotation).

Fix 2: Add a breakdown to control the path (instead of fighting the spline)

1. At the midpoint between two keys that pop, create a breakdown pose in the viewport that follows the intended path.
2. In the graph, ensure the breakdown sits on the correct side of the curve (no unintended dip or hump).
3. Replay: the breakdown should “steer” the interpolation into a clean transition.

Fix 3: Rotation issues (shortest path / gimbal)

• If a control flips: check rotation interpolation mode and consider switching to quaternion (if available) or adjust Euler filter settings.
• If gimbal is suspected: move the rotation load to a different control (e.g., distribute twist across upper arm/forearm) rather than forcing one axis to do everything.

D) Jitter / buzzing

Typical pattern: tiny changes every frame, often from over-keying or “fixing by nudging.”

Fix 1: Delete keys on ones (keep only what changes the motion)

1. On the jittering control, select the noisy range.
2. Delete keys on consecutive frames first (e.g., remove every key on ones), then evaluate.
3. If the motion becomes too loose, reintroduce two or three keys at meaningful moments (start, peak, settle) rather than re-keying every frame.

Fix 2: Smooth tangents without flattening intent

1. Use a curve smoothing tool lightly, or manually straighten small zigzags.
2. Preserve the larger curve shape (the overall timing and spacing) while removing micro-peaks.
3. Confirm in the viewport: the control should stop “buzzing” but still hit the same poses.

E) Dead holds

Typical pattern: the character freezes completely, or the hold lasts too long without internal change.

Fix 1: Re-time the hold length (make it intentional)

1. Mark the hold start and end frames.
2. Shorten or lengthen the hold based on intent: if it feels dead, it’s often too long for the amount of information on screen.
3. Shift the next action earlier/later while keeping the contact stable.

Fix 2: Add a controlled settle (not random motion)

1. Choose one or two controls only (commonly chest and head, or COG and clavicle).
2. Add a small settle over a few frames: a tiny overshoot and return, or a subtle drift to a more comfortable pose.
3. Keep it subordinate: the hold should still read as a hold, not a new action.

3) Prevention habits (so you don’t have to “rescue” shots later)

Keep poses clear (so timing edits don’t break readability)

• Before refining curves, verify that your key poses are distinct enough that you can recognize them in silhouette.
• If two poses look nearly identical, you’ll compensate with extra keys and create jitter or robotic spacing.

Control spacing deliberately (don’t let the spline decide)

• After setting keys, scrub frame-by-frame and watch the distance traveled per frame on the main driver (often COG/root or the hand in an action).
• If spacing looks accidentally even, you’ll get robotic motion; if it drifts after contact, you’ll get floatiness.

Confirm arcs early (before adding detail)

• Turn on motion trails/ghosting for hands, feet, and head early in blocking.
• Fix arc issues with a breakdown or tangent adjustment before layering secondary controls; otherwise you’ll “polish” a flawed path.

Lock contacts as soon as they matter

• The moment a foot/hand is meant to be planted, treat it as a constraint problem first, not a curve problem.
• Do not compensate for sliding by counter-animating other controls; that creates jitter and makes later retiming painful.

Work from big to small (avoid over-keying)

• Block and refine with a small set of controls; only add fingers, facial, and subtle offsets after the main motion is stable.
• If you catch yourself keying every frame, stop and ask: “Which single breakdown would solve this?”

4) Capstone mini-project: simple action with a required checklist

Pick one action: jump, reach-and-pick, or turn in place. Keep it 2–4 seconds. Use a simple rig and a clear camera angle (3/4 view is usually easiest for diagnosing spacing and arcs).

Option A: Jump (in-place or small forward hop)

1. Block keys: start pose, crouch, takeoff, apex, landing contact, settle.
2. Lock contacts: feet should be stable during crouch and on landing contact.
3. Refine timing: adjust the spacing into takeoff and into landing (avoid floaty long eases).
4. Graph pass: remove extra keys, fix tangent overshoot on vertical motion, add a breakdown if the path kinks.
5. Polish holds: ensure the settle doesn’t freeze; add a small controlled settle in torso/head.

Option B: Reach-and-pick (hand reaches a small object and lifts it)

1. Block keys: neutral, reach start, contact on object, lift, return/hold.
2. Lock contact: constrain hand to the object at grab; match transforms on the switch frame.
3. Check arcs: motion trail of wrist/hand should be clean; add a breakdown to steer around an obstacle if needed.
4. Fix pops: watch for constraint switch pop and tangent spikes in wrist rotation.
5. Reduce jitter: delete micro-keys on the hand after contact; let the constraint do the stability.

Option C: Turn in place (90–180 degrees)

1. Block keys: start, pre-turn, mid-turn, end.
2. Foot strategy: decide which foot is the pivot and lock it during the pivot phase.
3. Prevent snapping: watch hip/chest rotations for shortest-path flips; add a breakdown to guide the turn.
4. Hold management: if there’s a pause before the turn, re-time it so it reads intentional, not dead.

Required checklist (use this to self-diagnose before submitting)

• Timing: Are there clear faster and slower sections, or does everything change at the same rate?
• Spacing: Frame-by-frame, does the main control travel the intended distance per frame (no accidental evenness, no drift after stops)?
• Arcs: Are motion trails for hands/feet/head clean, with no sudden kinks?
• Anticipation: Is there a readable preparation that supports the main action (not just a tiny pre-move)?
• Follow-through: After the main action, do parts settle rather than stopping all at once?
• Overlap: Do different parts arrive at slightly different times in a controlled way (not jittery offsets)?
• Weight: Are contacts stable and does the body commit to support (no floaty settling, no sliding plants)?
• Graph hygiene: Are there unnecessary keys, tangent spikes, or noisy curves causing pops/jitter?

Submission format (for your own review)

• Provide a playblast at normal speed and one at half speed.
• Include one screenshot of motion trails (hands/feet/head) and one screenshot of the graph editor on the main driver control.