Animation Cycles and Loops

1Why cycles matter

A cycle is a piece of motion that repeats seamlessly: one stride of a walk that plays over and over as the character crosses the screen, one rise and fall of a chest as it breathes, one turn of a wheel. The point is economy: you animate a single loop's worth of poses and reuse it indefinitely, instead of keying every step across a long shot. Cycles are the backbone of character locomotion and idle motion, and once you are comfortable with them you get a lot of animation for very little keying.

2The Cycle interpolation mode

The tool that makes motion repeat is the Cycle interpolation mode, one of the options alongside Linear, Smooth, Step, and the eases. You set it the same way you set any interpolation: right-click a key in the Motion Graph and choose Cycle from the Interpolation menu, or pick it from the Interp dropdown in the inspector. Applied to a keyed section, Cycle repeats that section's motion forward through time automatically, so the values loop instead of settling at the last key. This is the single feature that turns one lap into an endless run.

3Preview a loop with the Loop toggle

To judge a cycle you need to watch it run round and round, and that is what the Loop transport toggle is for. Turn on Loop next to Play, and playback repeats your scene continuously instead of stopping at the end. This is essential for cycle work, because a loop's flaws only show up when it wraps from the last frame back to the first. Leave Loop on the whole time you are building a cycle, and keep the scene playing while you tweak, so every change is judged in motion, in context.

4The golden rule: first and last pose must match

This is the one rule that makes or breaks a cycle. For a loop to be seamless, the first pose and the last pose must match, so that when playback wraps from the end back to the start there is no visible jump. A cycle is a circle, not a line: the end has to hand off perfectly to the start. In practice you build the loop so the final keyframe is an exact copy of the first, then let the motion between them do the work. Get this right and the repeat becomes invisible.

5Anatomy of a walk cycle

A classic walk breaks into a handful of key poses you can block just like any move. The contact pose (front foot planted, back foot pushing off) is the anchor, and a walk has two of them, one for each foot. Between contacts sit the passing pose (the moving leg swinging under the body), the down (weight lowest, absorbing impact), and the up (body pushed to its highest). Block these extremes first, exactly as you learned when posing your first move, and you have the skeleton of a walk before any looping.

6Block the cycle's poses

Build the loop like any move: in Animate mode with Auto-key on, use the Pose tool to set each key pose at its frame along the timeline. Space the contacts, downs, ups, and passing poses evenly so the rhythm is steady. Keep the poses clean and readable, a cycle exaggerates every flaw because you see it over and over. Work in Step interpolation while blocking so you can judge each pose as a crisp hold, then bring in motion once the poses read well. This is the same blocking discipline from your first-move tutorial, applied to a loop.

7Apply Cycle and close the loop

With your poses blocked and the last frame matching the first, set the motion to repeat: right-click the relevant keys in the Motion Graph and choose Cycle from the Interpolation menu, or use the Interp dropdown. Now the values loop forward instead of stopping. Turn on the Loop transport toggle and play: the character should walk on and on with no stutter at the wrap. If it hitches, your first and last poses do not quite match, or a stray property was left uncycled, both easy fixes once you know to look.

8On ones and on twos: per-frame Hold

How many distinct drawings per second a cycle shows changes its whole texture, and you control that with the per-frame Hold field. Its readout says on ones (a new pose every frame, ultra-smooth) or on twos (each pose held for two frames, the classic hand-drawn look that most animation uses). Working on twos gives motion a traditional snap and halves the drawings you fuss over; on ones is smoother and suits fast or realistic action. Set the Hold to suit the feel you want for the cycle.

9Preview the texture with stepped playback

Alongside per-frame Hold, the transport has a stepped playback toggle reading On 1s, On 2s, or On 3s that previews your scene as if it were held on that many frames, without changing your actual keys. It is a fast way to check how your cycle would feel on twos or threes before committing. Flip it to On 2s and loop the walk to sample that hand-drawn cadence instantly. If you like it, set the per-frame Hold to match; if not, flip back. It is a try-before-you-commit preview.

10Idles and other repeating motion

Cycles are not just for walks. An idle, a character standing but alive, is a gentle cycle: a slow chest rise and fall for breathing, a subtle weight shift, maybe a blink. Build one loop of that soft motion, match first and last poses, set Cycle, and your character stays alive whenever they are not doing anything else. The same approach loops a spinning wheel, a bobbing float, a waving flag, or a flickering flame (pair a flame's flicker with a touch of Noise so it never looks mechanical).

11Making the wrap truly seamless

If a loop hitches, work through the usual suspects. First, confirm the first and last poses are identical, the most common cause of a jump. Second, check the interpolation across the wrap: the motion leaving the last key should flow into the first key just as smoothly as any interior segment, so tune the easing there too. Third, hunt for a single property, an arm, a tail, an eyebrow, that was not cycled or whose ends do not match. Fix these one at a time, looping constantly, and the seam disappears.

12The cycle mode toggle is not surfaced

One limit to know about. In some desktop animation tools you can flip a cycle between an absolute mode (the motion repeats in place) and a relative mode (each loop offsets from the last, useful for motion that should accumulate, like travelling forward). FoundryInk does not surface that absolute-versus-relative cycle toggle; there is only the single Cycle interpolation option. Cycle covers the common case, a repeating in-place loop, which is what walks, idles, wheels, and flames all need. For travel, move the character or camera separately.

13Turn a great cycle into an action

Once a cycle looks right, save the effort. Record it as an Action in the Actions panel with Add action, and you can stamp that walk or idle back onto the timeline anytime with the per-row Apply button ("Stamp these keyframes onto the timeline"). That means a reusable walk you build once and drop into any scene, or a library of idles you reach for again and again. A polished cycle is an asset, not a one-off, treat it like one and your future scenes come together far faster.

14What a good loop looks like

You know a cycle is finished when you can loop it for a full minute and never catch the repeat: no stutter at the wrap, no property popping, a steady rhythm, and motion that reads as continuous life. The feet plant without sliding, the arms swing in believable arcs, the breathing rises and falls evenly. Play it with Loop on and just watch for a while, if nothing snags your eye, you are done. Save it, bank it as an action if it is reusable, and you have a piece of animation that works forever for free.

Cycle questions