The timeline

The timeline family

The everyday frame verbs are also on the Animation menu, each aimed at the cel you have picked — or, with nothing picked, the drawing under the playhead on the layer you are on: play/pause and flipping to the neighbouring keys, inserting a keyframe, breakdown or inbetween, inserting an empty cell or a blank keyframe, extending and reducing an exposure, the cel clipboard, Delete and Delete and pull, onion skin and motion trail, and the playback range. Every one of them takes the selection when there is one, wherever the playhead is — Delete, Delete and pull, Insert empty cell and Insert blank keyframe cover all of it; the others act on the picked cel. None of them changes the layer you draw on. The cel's right-click menu stays the way to aim any of them at a particular cel — and keeps the dialogs (re-time, timing chart, markers), which need one to aim at.

Three views over the same animation share the bottom panel as tabs, and nothing you do in one is invisible in another:

Timeline	One coloured track per layer: drawings are dots, holds are the bars behind them, the camera is its own orange track on top, and the scratch track's waveform is its own band underneath. Drag a dot to retime that drawing; click anywhere else to scrub. The ruler numbers as closely as the frames are wide — every frame when they are wide, every second or third when they are narrow — and always numbers 1, 13, 25, so the second's cadence stays where you expect it. Scroll down a long list of tracks and the ruler, playhead chip included, stays pinned to the top of the panel — the X-sheet's ruler does the same over its rows. Ctrl+click picks dots and Shift+click ranges over the keys on that track, across the camera, the bones and the drawings alike — see Picking keys on the Timeline below.
X-sheet	The exposure sheet — the grid described below, where cels are edited, exposed, re-timed and annotated.
Graph editor	Value over time for the things that interpolate: the camera's position, zoom and rotation (drag a key dot — up and down for value, sideways to retime; a chip shows the value as you drag), and the measured spacing of your drawings — how far the ink actually moves between poses, the spacing chart read off the art itself. Even spacing is constant speed; widening is an ease; a spike is the drawing that pops. Double-click the plot to key the camera's framing at that frame (it keys what is already there, so nothing jumps — then drag it). Right-click a key for its easing into the next key, and to remove it. The legend on the bar toggles each curve, and its swatch says which colour is whose; the dashed Spacing (intended) curve is the same travel redistributed by the easing picked on the X-sheet bar — where the hollow dots and the filled ones disagree is the drawing that misses the ease. Spacing curves read the active layer. With one curve showing, the axis carries its numbers.

The layer you are on is always in view. Choose a layer — in the Layers docker, with the keyboard, or by picking on the canvas — and the Timeline and the X-sheet scroll just far enough to show its row, including the one that is behind as a tab when you bring it forward. A row already showing does not move, and the sheet keeps its place along the frames: only up and down changes.

The X-sheet

One row per layer, one cell per frame. Click a cell to go to its frame and pick it; the current frame is highlighted down the sheet.

A click never changes the layer you are drawing on. Click a cell in another layer's row and the playhead goes to that frame and that cell becomes the selection — so Delete, copy, cut and paste, extending or reducing an exposure, a timing preset and marking a keyframe or breakdown all act on it — while the next mark you make still lands on the layer you were on. Reading the timing of another layer, or tidying it, no longer costs you your place. Double-click a cell to go there and draw there: that switches to its layer. Clicking a layer's name at the start of its row, or picking it in the Layers docker, switches layer without moving the playhead. A click in your own layer's row simply moves the playhead, as it always has.

The cel that is highlighted is the one a command means, however it came to be picked. Ctrl+click picks a cel without moving the playhead, so with a cel picked on frame 10 and the playhead on frame 3, copy copies frame 10's cel, paste lands on it, and I or Insert breakdown inserts there — and the playhead stays on 3. With a block picked, copy takes the block's run and paste lands at the block's first cel, not at the playhead. When cels on several layers are picked at the same frame, a command that needs one of them takes the topmost row. With nothing picked — or only camera or bone keys picked on the Timeline tab — these commands mean the playhead's cel on the layer you are on, as before; Delete is the exception, and refuses rather than guess.

Three things stay with the layer you draw on, not with the picked cel: drawing itself, AI inbetweening, and stepping to the previous or next key (1 and 2), which walk the keys of the layer you are on. And one gesture still takes you to another layer besides the double click: dragging a drawing along another layer's row, and the commands on a cel's own right-click menu, which have always meant "here". A keyed cell holds a drawing; a hold repeats the drawing before it, which is what animating on 2s and 3s is made of.

What a cell shows

The drawing's number, the way a paper sheet writes it. Drawings are numbered along their row, 1 first. The number sits where the drawing lands and a line runs on through the cells it is held across, so a row on 2s reads 1 — 2 — 3 — and you can count the timing without opening a drawing. How the number is written says what kind of drawing it is: bold for a keyframe, ringed for a breakdown, quieter for an inbetween. A × is a blank drawing, a keyframe with nothing on it yet.

The selector on the X-sheet's own bar — also Edit → Configure → Timeline ▸ A cel shows — offers two other ways to read the same row:

Numbers	The default, described above.
Dots	The Timeline's language: a filled dot for a key, a ring for a breakdown, a small dot for an inbetween, a white square for a blank drawing, on a bar along the hold.
Pictures	A small picture of each drawing in its cell, on a cell tinted by its kind — violet for a breakdown, teal for an inbetween — since a picture cannot say that on its own. In the other two the number or the mark says it, and the cells stay plain. The only one of the three that renders anything: every drawing on the sheet is drawn again, small, and kept up to date as you work, so a long scene pays for it. Chosen, it makes the pictures; left, it lets them go.

It is a preference, not part of the document: it changes how you read the sheet, never a pixel of the art, and a file opened on another machine shows whatever that machine prefers.

Numbers count the drawings on the row as they are today, where every exposure is a drawing of its own. A cycle that repeats the same drawings — 1 2 3 4 1 2 3 4 — needs one drawing to be exposable in several cells, which is Planned.

Two kinds of cell look empty, and they are not the same thing. A plain empty cell is inside the scene: it is a hold or a blanked drawing, and a mark on it keys a drawing. A hatched cell is past the end of the scene — there is no frame there yet.

You can still go there, and that is how a scene gets longer. Drag the playhead onto a hatched cell, or click one, and the playhead stands on it; the canvas shows no drawing, because there is none, while onion skin and any armature still show so you have something to work against. Nothing has changed in your document yet — scrubbing out there costs nothing and leaves no undo step.

The scene grows when you edit, not when you arrive. Make a mark, or pose a rig, on a hatched cell and the scene extends to reach it. The frames in between become holds, so the drawing that was last up stays up across the gap — which is how you hold one drawing for ten frames: drag the playhead ten frames out and draw. Extending is its own undo step, so one undo takes the mark back and another gives the length back.

How far out you can go is however far the sheet is drawn — if you can see the cell, you can stand on it.

Playback is not affected. Playing runs to the end of the scene, or to the start and end you set for the playback range, and never out into the hatching. Scrubbing is free; playing is bounded.

When the sheet cannot show what is happening

The X-sheet is the exposure sheet: ink, and when it is exposed. The camera and the armature are animated too, but they are not part of the exposure, so they live on the Timeline and have no cell here. That division is deliberate — a camera key belongs to no layer, and a row for it in the drawing grid would change what the grid means.

What it costs is knowing that something happens at all. Four drawings on the sheet and a pose on frame 9, and nothing in front of you says frame 9 is different.

Configure ▸ Timeline ▸ Mark frames where the camera or a bone is keyed turns on a small square under the X-sheet's frame number: orange for a camera key, blue for a pose key, in the Timeline's own track colours, and two side by side on a frame carrying both. It marks only the frames that actually hold a key — not the frames a camera moves across, which are interpolated and are not decisions you made.

It is off by default, and off means absent: a document with no camera and no rig shows nothing and costs nothing, and the sheet stays a sheet unless you ask it to say more.

Picking keys on the Timeline

The X-sheet's cells are one way to pick things; the Timeline's dots are the other, and they are the same selection. Cels you pick on one show up on the other — the two are views over one animation. Camera and bone keys simply have no X-sheet cell to appear in.

Ctrl+click a dot to add it or drop it. Shift+click takes the keys between the last dot you picked and this one, on that track — the keys, not every frame between them, because an empty frame has nothing to retime. A selected dot wears a white ring.

A plain click on a dot that is not selected makes it the selection, so the drag that follows moves what you can see is picked. A plain click on one that is already selected leaves the selection alone — otherwise the press that starts a drag would throw away the five keys you were about to move. To narrow a selection back down, click a dot outside it.

Dragging retimes everything selected, by the same number of frames, as one undo step. This is the point of picking across kinds: a camera move, two bone keys and a drawing shift together, which is what "push this beat two frames later" means. Drag a dot that is not in the selection and only it moves.

If any part of the selection would land before frame 1, the whole drag is refused rather than moving some of it and clamping the rest — a partial shift closes the gaps you were keeping.

Retiming and the key clipboard cross kinds; deleting does not. Moving and copying are the two things a camera key, a pose key and a drawing genuinely have in common — "this beat, two frames later" and "this beat, there too" are one gesture each. Deleting is not one verb with three names: removing a camera key, unkeying a bone and clearing a drawing leave different things behind. So each row's right-click offers its own delete — the pose row's Delete covers the pose keys in the selection and leaves a camera key or a drawing beside them alone.

The timeline's right-click menu

Right-click a key dot for its menu, on every kind of row:

• Copy / Cut — the whole selection when the dot is in it, the dot alone when it is not. See Copying keys below; cut removes exactly what it copied, as one undo step.
• The row's own verbs: a camera key offers Ease into next (the graph editor's easing menu, where the key actually is) and Remove camera key; a pose key offers Delete this pose key or Unkey this bone here; a drawing offers Clear drawing, which keeps the timing the way the X-sheet's Delete does.
• Go to frame — jump the playhead to the key.

Right-click an empty stretch of a track for the verbs that need a frame rather than a key: Paste keys at this frame, Key the camera here (on the camera's row) or Key the pose here (on the armature's rows) — both key what is already interpolated there, so nothing jumps — and the playback range's start and end.

Copying keys

Copy takes whatever the dot selection holds — camera keys, pose keys, single bones' entries, drawings — and Paste lands the lot with the earliest key on the frame you aim at, every distance between them kept. That is the clipboard's face of the mixed retime: a camera move, two bone keys and a drawing copied as one beat and pasted as one beat, one undo step.

What landing means is each kind's own replace: a camera key or a whole pose key on the destination gives way; a single bone's entry joins the pose key already there (seeding a new key from the interpolated pose first, so pasting one bone never snaps its neighbours to rest); a drawing replaces the cel on its frame, extending the scene if it must. A key whose home is gone — the camera removed since the copy, a bone deleted, a layer locked — is skipped and the status line says so.

This clipboard is deliberately separate from the cel clipboard (above): that one is a sequence of drawings on one row, pasted consecutively with the holes closed; this one is a set of keys at their distances. Copying cels for re-timing wants the first; copying a beat wants this.

Copy selected keys and Paste keys at playhead are in Edit → Configure → Shortcuts under Timeline, unbound by default — Ctrl+C already means the selection, the cels or the layer, and a further silent reading of it would be a trap.

The key inspector

Select exactly one key and its numbers appear on a strip under the tracks: a camera key's X, Y, zoom and rotation; a bone key's X, Y and rotation (its departure from rest — zero means the bind pose); a drawing's layer depth, the Scene panel's number editable where the key is. Type or spin, and the change lands in the key itself — the same values the graph editor drags, as digits.

The strip is absent when nothing is selected, and absent when several keys are — it shows one key's truth rather than an average. The armature summary row's key is a whole pose, so it offers the hint to open Bones and pick one bone's key instead of pretending a pose is three numbers.

The scratch track

Audio is optional and absent until you add it — the same rule the camera follows. ♪ Add audio on the Timeline docker's bar imports a WAV file, and the timeline grows an Audio band: one bar per frame, tall where the sound is loud, so a beat or a syllable can be found by eye and a drawing timed onto it.

On import you choose where the sound lives:

• Reference the file (the default): the document stores where the file is (relative to the document when it lives nearby, so a project folder moves as one thing). Keep editing it in your audio tool — the timeline reads the file as it is on disk. If the file goes missing the bar shows a missing badge and the track waits, silently, for it to come back; your timing is never lost with it.
• Embed a copy: the sound travels inside the document, which then survives being shared without the WAV beside it — at the cost of carrying those megabytes through every save. The dialog shows the size before you choose.

Either way the offset, volume and mute you set are part of the document.

The clip is a bar you can take hold of. In the Timeline docker the sound spans its frames as a bar around the waveform: drag the body to slide the whole clip for timing, drag either end to trim its in and out points — cut the slate off the front, end on the beat — all without touching the source file. Trimming eats or restores source frames; the trimmed window is what plays, scrubs and exports. Footage clips get the same bar, one row per clip, with the same body-slide and edge-trim handles.

Cut a clip where the playhead is. Put the playhead inside a bar, right-click it and choose Split at frame n. The bar becomes two, and from then on each section slides and trims on its own — move a line of dialogue three frames later without moving the rest of the take, or hold a piece of footage while the shot after it stays where it is. Cut again to make a third; a cut at a section's own edge is refused, because there is nothing there to divide.

Two things sections will not do. They never overlap: drag one into its neighbour and it stops against it, so the timeline can always say what is playing at a frame. And splitting never edits the source — a section is a window onto the file and a place to put it, so nothing you do here can lose sound or frames you have not got a copy of.

A split clip's timing is no longer one offset and one trim, so exports lay the sections out on the timeline first: gaps come out as silence, and the sound lands frame-for-frame where the bars say it does.

The bar's controls: Mute, volume, the start frame (negative trims a lead-in without editing the file), and ✕ to remove the track — the file itself is untouched.

It plays. Press play and the sound runs in sync with the frames, looping when playback loops and following the Speed % control (faster playback raises the pitch, the way scrubbing tape does). Dragging the playhead plays the slice of sound under each frame — the track read a syllable at a time, which is how a mouth is matched to a line. Playing backwards is silent on purpose; reversed audio is noise, not information. On a machine with no sound device the track simply stays quiet — nothing breaks.

Markers, notes and events

A marker is a named point on a frame, shown as a coloured chip on the ruler. One thing, three uses, and which one you get depends on what you fill in:

A label	The chip on the ruler — "contact", "passing". Keep it short; it has to fit.
A note	Prose about the frame, as long as it needs to be: the hand pops here, fix on 2s. It is not drawn on the ruler; it appears in the notes list and on hover. Writing a note on an unmarked frame creates the marker for you.
An event	Tick it and the marker is exported to your game engine as an animation event — OnFootstep at frame 7. Off by default, because most markers are notes to yourself and a game has nothing to do with them.

Detect contacts (in the onion bar's ⚙, under Analysis) reads your sequence's footfalls off the lowest ink and marks each one with a "contact" marker — one undo step, and any frame you already marked is left exactly as you marked it. The jump arc analyser fits between contact markers, and an exporter can tick them as events like any other marker.

Renaming a marker keeps its note and its event tick. Next / previous marker walks between them, which is what makes them useful on a long sheet rather than labels you have to find by eye; walking past the last one stays where it is rather than jumping back to the first.

A tag is the same idea over a range rather than a point: a name, a start and an end — "walk", "run", "idle". That is what an engine calls an animation clip, and it is what lets one sprite sheet hold several animations. A tag can carry a note too, for when the remark is about the whole cycle rather than one drawing.

Right-click a cel for: insert frame, mark as, insert empty cell, insert blank keyframe, extend or reduce exposure, Delete, Delete and pull, copy, cut, paste, markers, and the playback range.

Insert frame (a keyframe, breakdown or inbetween) on an empty cel turns that cel into a blank drawing. On a cel that already has a drawing it adds a new, blank one after that drawing's hold and moves the rest of the row along one: with A held for two and then B, inserting on either A cel gives A A new B, so A keeps its timing. The playhead moves to the new drawing. I and the Animation menu's Insert items do the same at the playhead (or the picked cel). To change what a drawing is — a key into a breakdown, say — use Mark as, which re-marks the picked drawings in place and moves nothing.

What a cel can be. A frame on a row either has a cel or it does not. A cel is either empty — a hold, showing the drawing before it, the way Krita does it — or it carries a drawing, and a drawing with nothing on it yet is a blank keyframe, the white cel. A drawing can be a keyframe, a breakdown or an inbetween; an empty cel has no type of its own, since what it shows is borrowed. Where there is no cel at all — past the end of the scene — the sheet is hatched. Every row runs to the end of the scene; a row that stops short of it is filled with empties.

Two deletes, named for what they leave behind.

	Key (over the X-sheet)	What happens
Delete	Delete	The drawings in the selected cels go and the cels become holds. Every slot stays, so nothing after them moves.
Delete and pull	Shift+Delete	The selected cels are removed and the rest of each row is pulled back, padded with holds at the end, so the scene keeps its length and the other layers do not move.

Delete and pull on empty cells after a layer's last drawing ends the scene at its last drawing. On their own those cells cannot be pulled back — every row runs to the end of the scene — so the scene is trimmed instead: it now ends one frame after the last drawing on any layer, and every layer's empty cells past that point go with it. One undo puts them all back. If another layer still has a drawing on the last frame there is nothing to trim, and the status line says which layer.

Select the same frames on every layer and Delete and pull takes them out of the scene. Every layer loses its cel at those frames, the whole sheet is pulled back, and the scene gets that many frames shorter — what you want when a beat is a frame too long. The paper does not need selecting (it is not animated, and it keeps showing on every frame that is left), and a document with one drawing layer makes every selection a column, so there Delete and pull always shortens the scene. A column is refused while any drawing layer is locked or sits in a locked folder, because removing the frame from the others would slide them out of step with it; and a scene is never shorter than one frame. The 🗑 on the timeline bar does the same for the frame under the playhead.

Insert empty cell puts a hold at the cel: the new cel shows the drawing before it, and the cel you clicked and the rest of its row move one frame later — how you make a drawing arrive a frame late without touching anything else. Select a run of three cels and three holds go in at the start of the run. If the row runs past the end, the scene grows to fit, as extending an exposure does. Select the same frames on every layer and it is a column insert: every layer moves along, the paper stays put, and reference strips move with the frames. It has no default key; give it one in Edit → Configure → Shortcuts, where all four are listed under Timeline. (Before, this was called Insert blank frame; a key you gave it then still works.)

Insert blank keyframe — I over the X-sheet — turns the selected empty cels into blank keyframes, in place: white cels with nothing drawn on them, ready for the next drawing, and nothing else on the row moves. Cels that already hold a drawing are left as they are; to start one of those blank, Delete it first. Past the end of the scene it grows the scene to reach the cel, as drawing there does. Over the Timeline docker I still inserts a key at the playhead, and everywhere else it is still the eyedropper. Drawing on an empty cel makes a blank keyframe for you on the first mark, with the setting Drawing on a held cel at its default.

Each of the four is one undo step, however many cels and layers it reached. The keys answer only with the pointer over the X-sheet: over the canvas Delete still clears the selection, and over the Layers docker it still deletes a layer.

Folders are rows on the Timeline and the X-sheet, in the same order as the Layers docker. Click a folder's chevron to fold it: the layers inside lose their rows and the folder's own row stands for them, with a mark on every frame where anything inside it — at any depth — has a drawing. Open it again to get the rows back. A character kept as rough, line and colour layers can be one row while you time it and three while you draw it.

Folding here is separate from the Layers docker. Collapsing a folder in the Layers docker does not fold it on the sheet, and the other way round, so the layers stay within reach where you paint while the sheet stays short. The fold is saved with the document and is not an undo step. Both surfaces fold together — the Timeline and the X-sheet are two views of one sheet.

Drag a folder's mark to move the whole pose. A folder's row is a summary, and its marks are handles: drag one along the row — on the Timeline or on the X-sheet, folded or open — and every drawing inside the folder on that frame moves with it, each along its own layer, as one undo step. Layers inside with nothing drawn on that frame are left alone.

It moves whole or not at all. If a layer inside already has a drawing on the frame you drop on, nothing moves and the status line names the layer — unlike dragging a single drawing, this never replaces one, because it reaches layers whose rows may be folded out of sight. Nor does it move while anything inside is locked. A folder's marks cannot be selected, copied or deleted; open the folder for that.

What is folded away is out of reach of everything else: folding drops any cels inside it from the selection, and a block swept across a folded folder leaves its layers out, so nothing you cannot see is ever deleted. On the X-sheet a folder and the layers inside it share the folder's colour.

Pin the rows you are timing, and hide the rest. Right-click a layer — in the Layers docker or on its name in the X-sheet — and choose Pin to timeline; a folder has the same item on its header's menu and a pin on its row in the X-sheet. Once anything is pinned, Pinned only appears on the Timeline's and the X-sheet's bars. Switch it on and both show just the pinned layers and folders, plus the layer you are drawing on, which is never hidden, and the folders those sit in so the sheet is still a tree you can fold. A pinned folder brings everything inside it. Switch it off and every row is back; the pins stay for next time.

Pins and the switch are saved with the document and are not undo steps. As with folding, a row that leaves the sheet leaves the selection, so nothing out of sight is deleted. Both verbs can be given keys in Edit ▸ Configure ▸ Shortcuts — Show only pinned rows and Pin or unpin the active layer — and have none by default.

Drag a drawing along its row to move it — no modifier, with a mouse or a pen; a label naming the frame you picked up follows the pointer. Hold Ctrl as you drop to leave the original where it was and place a copy. This is how timing is changed by hand: pick the drawing up and put it on the frame it belongs on. Whatever the frame you drop on held is replaced, and dropping past the end of the scene makes the scene longer.

Drag a selected drawing and everything selected goes with it, by the same number of frames, each drawing along its own row. Select a run on one layer to slide a whole phrase later, or the same frames down several layers to keep them in step. It is one undo step, Ctrl copies the block, and a block that would push a drawing off the front of the sheet does not move at all. A drawing that is not part of the selection moves alone and leaves the selection as it was.

Drag from an empty cel to select a block — every frame you sweep on every row you sweep, as in a spreadsheet. Shift+click does the same from the last cel you clicked, so a block can be made in two clicks and resized with a third, and it is the way to start a block on a drawing, since dragging a drawing moves it. A block stops at the end of the scene: there are no cels in the hatch. A plain click still moves the playhead and clears the selection.

Ctrl+click picks cels one at a time, including ones that are not next to each other and ones on other layers — every third cel of a cycle, or the same two cels across four layers. Ctrl+click a picked cel again to drop it. Shift still ranges from the last cel you clicked, across rows as well as frames, and re-ranges rather than adding a second block, so it is the way to correct an overshoot.

Everything on the cel's right-click menu covers the selection — insert a key, breakdown, inbetween or blank frame, extend and reduce exposure, Delete, Delete and pull, and the three re-timing commands. The cels you left out are left alone, and an action aimed at a cel that is not in the selection takes that cel alone, so right-clicking somewhere else is never a trap.

The ones that change the length of a row — extend, reduce, Delete and pull, insert empty cell — work from the end of the row backwards, so the frames they add or remove never shift the cels you picked further along. The re-timing commands treat a picked-out selection as runs rather than as one span: select cels 1, 2 and 5 and you re-time a pair and a single, not everything from 1 to 5.

Copy, cut and paste work on one row, because a cel clipboard is a sequence of drawings on one layer; copying a picked-out set takes the cels you chose in order and pastes them consecutively, holes closed up. If the selection reached other layers, the status line says which were not copied rather than pretending otherwise.

The right-click Paste pastes onto the cel it was opened on. Ctrl+V pastes copied cels onto a new layer above the active one instead, starting at the playhead, so nothing already on the sheet is replaced.

Timing presets

A timing preset is a pattern of hold lengths — how long each drawing in a run is held. 2 is on 2s. 1, 1, 2, 3, 4 is a slow-in: two snappy frames, then progressively longer holds.

The picker and Re-time are on the timeline bar. Shift-click a range first, or use Re-time to … in a cel's right-click menu to do one cel.

Applying one re-spaces the drawings that are already there. It never makes a drawing and never deletes one — the worst it can do to your art is change its timing, and one undo puts that back.

The pattern decides the length, not your selection. Twelve drawings put on 2s take twenty-four frames, so the row gets longer and the rest of it moves down; the same twelve put back on 1s take twelve, and it gets shorter. The status line says which way it went. If you want to thin a range — keep every second drawing and discard the rest — that is a different, deliberately destructive operation.

Six patterns are built in: on 1s, 2s, 3s, 4s, and a slow-in and slow-out. Behind the ⚙ beside the picker you can save your own: type a name and a pattern (commas or spaces, both work) and it is there next time you open the app. Your own patterns can be deleted; the built-ins cannot.

Compared with
A symbol	carries drawings. A timing preset carries their spacing — the half a symbol cannot express.
A template	gives a new document its shape, once, at creation. A preset re-times drawings you already made, any time, as often as you like.

Drawing on a hold

A cel that holds an earlier drawing is not a drawing of its own, so a mark on one has three honest readings — and which you mean depends on how you work. Edit → Configure → Timeline → Drawing on a held cel chooses.

Start a blank drawing (the default). The cel becomes a new, empty drawing and the mark lands on it — the next sheet of paper. The onion skin shows the drawing before it, the way a light table does, so you draw the new pose over the old one without the old one being part of it. With onion skin off, the held drawing disappears from this frame under your first mark: the frame no longer holds it, and the earlier frame keeps it exactly as it was.

Start from a copy. The cel becomes a drawing of its own that starts as a copy of what the hold was showing — strokes, imported pixels and placed symbols alike — so the mark you just made is the only visible difference. Right when you work by altering the last drawing rather than redrawing it. (This was the default before; a settings file from then is read as the new default, so pick it again here if you had chosen it.)

Edit the held drawing. The mark joins the drawing being held and appears on every frame holding it. Right when the hold is deliberate and you are still working on that one pose — touching it up without breaking the hold. It governs the editing tools too: with it set, a move on a hold moves the held drawing and keys nothing.

Either of the first two is what every animation tool does: the timeline shows a drawing where you made one, instead of your stroke turning up on the earlier frame too.

A mark is anything that adds to the page — the brush, the eraser, shapes, gradients, the pen, new type, filling a selection, placing a symbol. Anything that works on what the hold is showing always starts from a copy, whichever choice is set, because a blank page would leave it nothing to act on: moving or transforming the drawing, dragging a placed symbol, reshaping a line, moving, nudging, recolouring, cutting or deleting selected lines, Delete on a marquee, clicking into type the hold is showing to retype it, the bucket (it finds its edges in the held lines, so colouring held line art colours it on this frame), blur and smudge (they rework the paint already there), and painting on an alpha-locked layer (it paints only where there is paint). Selecting on a hold authors nothing — looking around is not editing, and only the edit that lands makes the cel a drawing of its own.

An eraser on a hold, with a blank drawing set, does nothing — there is nothing on a blank page to rub out — so nothing is recorded and the cel stays a hold. To rub out part of the held drawing on this frame only, choose Start from a copy, or delete it with a marquee, which always copies.

The key happens when you commit the edit, not when you pick the tool up. Pressing Ctrl+T on a hold and then Escape leaves the timeline exactly as it was, and so does clicking without dragging — a click with the shape or gradient tool, a fill that finds nothing to fill, or type with no letters all hand the new drawing back. The pen keys only when its line is finished, so a path of one point, or one left unfinished, leaves the hold as it was. A cel becomes a drawing of its own when you actually change something, never because you were looking at it.

A transform whose scope reaches past this frame — This layer, every frame, or the whole animation — keys nothing, even when you opened it on a hold and widened the scope afterwards: it moves the drawings themselves, so every frame holding one moves with it.

Keying is a separate undo step from the mark that prompted it: one undo takes the stroke back and leaves the new drawing, a second takes the drawing away and restores the hold.

The volume and balance check

View → Volume and balance check reads the drawing and reports — it never touches your input the way a guide does. Per frame, on the layer you are standing on, it measures two things about the ink:

• Volume — the ink's area, shown as a band of bars under the timeline's tracks. Squash and stretch preserves volume: a ball that squashes must widen, so a level skyline is on-model and a step in it is a drawing that swelled or shrank — the drift no single frame can show you. Frames that drift further than the tolerance from the shot's median turn warm.
• Balance — the ink's centre of mass, drawn on the canvas as a dot per frame with the arc they trace, onion-skin style: the current frame's dot is the solid, ringed one. A walk reads wrong when this arc jitters, and a pose reads off-balance when the dot is not over the support foot.

The centre of mass is honestly the centroid of the ink: it equals the physical centre of mass only if the character has uniform density, which is the right lie for a drawing aid. And "the character" is whatever is on the active layer — effects, props or a second character on other layers are deliberately not counted, so standing on the character's layer is how you say what to measure.

Holds are measured once — a scene on 2s costs half its frame count — and the readings refresh a beat after each edit rather than during it, so the checker never adds to the pen's own latency. The allowed drift is Edit → Configure → Timeline → Volume check, ten percent unless you say otherwise.

The timeline's size

Frames on the timeline's own bar sets how wide a frame cell is. Narrow enough to see the shape of the timing on a two-hundred-frame scene, wide enough to read the numbers, or the pictures, on a twelve-drawing cycle — it depends entirely on what you are doing, so it is a slider rather than a constant. The same number is in Edit → Configure → Timeline.

The playback range

The scrub bar carries the loop bounds. Hover it and two grips appear — one at each end of the range, with a bar between them showing what will play. Drag either to move that bound; it settles onto whole frames as you go, so what you see while dragging is what you get. The two cannot cross: push one past the other and it pins a frame away.

With no range set yet the grips sit on the ends of the whole timeline, so the first drag narrows it rather than starting from one frame somewhere arbitrary.

Alt-click a grip, or anywhere between the two, to give the range back — between them is the bigger target and the region the range is actually about. Right-click the scrub bar for the same thing as a menu item.

Grabbing a bound and moving the playhead are nearly the same gesture in nearly the same place, so the grips win where they are and clicking anywhere else on the bar still scrubs.

The Set playback start / end items on a cel's context menu still work and do the same thing; the grips are the version you can aim. The Animation menu carries the same pair, taking the playhead's frame as the bound.

The range belongs to the document. It is saved with it and comes back when you reopen the file; a document that never had a range saves none. Setting it is not an undo step: undo a few strokes to compare, set a range to play that part, and the strokes are still there to redo. Undo and redo leave the range you have alone — except when the step being undone is one that moved it, which the next paragraph is about.

It stays on the drawings it framed. Hold the last drawing in the range a frame longer (Extend exposure) and the end moves with it; insert or extend before the range and both bounds move along. The same goes for every edit that moves cels along a row or the whole sheet — Reduce exposure, Insert empty cell, Delete and pull, adding or removing frames, re-timing — so the range keeps playing the same drawings whichever verb moved them. An edit on one layer moves the range for the whole scene, since there is only one.

Looping

Playback loops, because a cycle is usually what you are watching and stopping after one pass means reaching for the button every time. 🔁 on the timeline bar turns it off, and it then plays the range once and stops on its last frame.

Playback

Space plays and pauses. Transport buttons step, jump and loop. Set fps and a speed percentage. Holds resolve properly, so a drawing exposed on 3s stays up for its full three frames.

Playback keeps time rather than counting frames. A scene set to 12 fps runs at twelve frames a second of real time, and each frame is held the same length as every other — which matters more than it sounds like it should, because an uneven frame length is what the eye reads as stutter even when the average rate looks right. It also keeps the picture with the scratch track instead of drifting away from it over a long take.

If the machine cannot keep up, frames are dropped so the timing stays true rather than the animation running slow. After a real interruption — a dialog, a laptop lid, a breakpoint — playback picks up from where it is rather than racing to catch up on what it missed.

While it plays, the frames just ahead of the playhead are being built on another processor core, so a drawing you have not reached yet is usually ready before you get to it. The first run through a scene used to be the rough one for exactly that reason — every drawing was built at the moment it was needed. There is nothing to switch on and nothing to wait for; if you want to know whether it is keeping up on your machine, Help ▸ Write a render report says so.

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