Week 09 · Animation I: cycles & principles — FMX 320 Animation for Games

By the end of this session you can

Key the four core poses of a walk — contact, down, passing, up — on your own rig.
Use Blender's graph editor to control timing and spacing so the motion carries weight.
Make a cycle loop seamlessly by matching first and last frames and cycling the F-curves.
Add weight and overlap so the walk reads as alive, not mechanical.
Export a loopable clip that reads at gameplay speed and holds up from any camera angle.

Mon 2:00 · Brief What makes motion loop and read

A game walk is not a film walk — it repeats forever, plays at a fixed speed, and gets watched from angles you didn't choose.

Poses first, then timing

You animate a walk in two layers. First you set the key poses — the storytelling frames that define the action. For a walk those are contact (foot lands, legs spread), down (weight drops onto the planted foot, the body's lowest point), passing (the free leg swings under the hips, the body's highest point), and up (the push-off as the body rises again). Get these four right on both sides and you have a walk. Get them wrong and no amount of polish saves it.

Timing and spacing are different things

Timing is how long the action takes — the number of frames. Spacing is how the in-between values are distributed across those frames, and it's where weight lives. Even spacing feels floaty and robotic; eased spacing (slow-out, slow-in) feels like mass responding to gravity. You control both in the graph editor by shaping F-curves and their handles, not by scrubbing the timeline and hoping.

Looping and readability

A clip loops when the last frame's pose and tangents match the first. In Blender you enforce this with a Cycles modifier on the F-curves and by making the last keyframe a duplicate of the first. Readability is the other half: the silhouette must be clear at every frame, because in engine the player picks the camera. If the passing pose reads as mush from a 3/4 view, fix the pose — don't blame the camera.

State of the Art · Motion capture in your pocket

Epic's free MetaHuman Animator now does markerless, single-camera facial and body mocap from phone video, putting usable performance capture within reach of a solo student — and Unreal ingests it through retargeting onto your skeleton. Hand-keyed animation stays the gold standard for stylized, readable game motion. Discussion: for your character, when do you capture and when do you key?

MetaHuman Animator markerless mocap

Mon 2:45 · Guided lab Key a walk on your rig

Work in Blender with the rig you built in Week 6 — reference video open beside your viewport the whole time.

Set a 24-frame stage
Frame range 1–25 with frame 25 as the return-to-start. A one-second, 24 fps loop is the standard starting point; you can retime later. Turn on auto-key and set your bone rotation mode so curves stay readable.
Block the contact poses
Key contact on frame 1 (right foot forward) and frame 13 (left foot forward). Legs spread, arms opposed to legs, torso leaning slightly into the motion. These two frames define the whole walk — spend real time here.
Add down and up
On the quarter frames key the down pose (body lowest, planted knee bent, weight committed) and the up pose (body highest, pushing off the ball of the foot). These give the walk its vertical bounce and are where weight starts to appear.
Add passing poses
Between contacts, key the passing position — free leg directly under the hips, foot lifted to clear the ground, hips at their peak. Check the silhouette from the side and a 3/4 view.
Shape timing in the graph editor
Open the graph editor and ease the vertical hip curve: slow-in at the top, snappier through the down. Flatten handles at pose extremes. This is where even, floaty motion becomes weighted motion.
Make it loop
Copy frame 1's pose to frame 25, then add a Cycles F-modifier to the moving curves. Scrub across the loop point — any pop means the first and last tangents don't match. Fix the handles until it's invisible.
Add weight and overlap
Offset the arm swing a frame or two behind the legs, let the head settle a beat late, and add a small hip rotation and shoulder counter-rotation. Overlap is what turns a rig test into a performance.
Export the clip
Push the action down as a named clip and export via File > Export > FBX with Bake Animation on, ready to import into Unreal next week. Confirm it plays looped at gameplay speed.

Wed 2:00 · Agent lab Draft the plan, keep the craft

Use the agent to pressure-test your intent and catch your blind spots — the keys stay yours.

Prompt 1 · Feel to timing notes

Here is the feel I want for my walk cycle: "heavy, tired, cautious." Draft pose-timing notes for a 24-frame loop (contact, down, passing, up on both sides) that would sell that feel — where to hold, where to drag, how much vertical bounce — and give me a short reference-shot list of real-world footage I should study to nail it.

Watch for: does the plan match the mood you actually want? Push back where it contradicts what your reference shows. The agent drafts intent; your eyes and hands decide the frames.

Prompt 2 · Self-check list

List the most common mistakes students make in a hand-keyed walk cycle — foot sliding, floaty weight, twinning, hitching at the loop point, dead arms — and turn each into a concrete thing I can check for in my own Blender scene right now.

Verify: run each item against your actual cycle. Foot sliding and loop pops are objective — go find them. Log which mistakes you were making before the agent named them.

Before you call it done

The four core poses read clearly on both sides, from side and 3/4 views.
The loop is seamless — no pop or hitch when scrubbing across the seam.
No foot sliding; planted feet stay locked while in contact.
Weight and overlap are visible; arms and head don't move in dead sync with the legs.
Zip a post-session snapshot and add an AILOG.md entry noting which prompts you used and what you accepted or rejected.

Wed 3:10 · Crit / share Loop-point roulette

We play each walk on loop, at gameplay speed, on the big screen — no narration. The room calls out the first thing that breaks: a slide, a floaty hip, a twinned pose, a loop pop. This is the fastest way to train your eye, because the loop hides nothing when it repeats twenty times. Bring your cycle in whatever state it's in; a rough walk that loops beats a polished walk that hitches.

Homework — due before Week 09

Task	Deliverable
Finish and polish your walk cycle from lab.	A clean, looping walk clip on your rig, exported and ready for Unreal.
Author a second locomotion clip — a run or a jog.	A looping run/jog clip at a faster cadence, matched to your character's weight.
Prep an idle and read ahead on Unreal's Animation Blueprints.	A short idle clip plus notes, brought to Week 9 for the Anim BP lab.

Resources

Blender animation — keyframes, actions, and the animation workflow.
Blender graph editor — the F-curve, handle, and Cycles-modifier work timing and looping depend on.
Unreal Animation Blueprints — how your clips will live in engine, and the 12-principles lens for game motion.