Rig
The Rig tool — drawing bone chains, the edit/pose/weights split, FK posing and IK handles, automatic and painted weights, jiggle, bendy joints, and joint fixes.
Reference
- Tool
- Rig
- Section
- Rig
The Rig tool puts a skeleton inside a drawing and poses it. You draw the bones as strokes, the drawing is bound to them automatically, and from then on dragging a bone moves the artwork.
Rigging and posing are two different activities and the tool keeps them strictly apart.
Edit and Pose
Builds and fixes the skeleton: draw chains, drag joints, select, delete, split. The artwork never deforms in this mode — it shows its rest state throughout. The tool always opens here.
Deforms the artwork. Drag a bone to rotate it; drag an IK handle to make a limb reach.
Paints which bone a part of the artwork follows, for the places the automatic weights get wrong. The art holds its rest pose while you paint.
Posing never happens while rigging. A pose drag in Edit bones is refused outright rather than silently applied, so repairing a skeleton cannot disturb the pose you already made, and the rest position you are editing is always the one you are looking at.
The Marquee picker sits in both modes once the layer has bones, and chooses the shape of a selection drag.
Box or Lasso, shown as two icons. Sets how a selection drag encloses bones.
Edit bones
The panel reads: "Draw strokes to add bone chains — corners become joints. To GROW a limb from a joint: start the stroke just OUTSIDE the joint's handle (it snaps on), or select the bone and tap “Grow bone from tip”. Drag a joint handle itself to REPOSITION it. Tap bones to select."
Drawing chains
Draw a stroke along a limb and it becomes a chain of bones. Corners become joints: the stroke is
simplified, and the corner threshold scales with the stroke's overall extent rather than its length,
so a long wavy stroke keeps its corners while drawing-hand jitter smooths away. Chains are connected —
each bone's head sits at its parent's tail — and are named bone 1, bone 2 and so on.
Auto, 1, 2, 3, 4, 5. On Auto, the corners in the stroke decide the joints, up to a ceiling of eight bones per stroke. On a fixed count the stroke is divided into that many bones of equal length.
Repurposes the drag gesture for selection, so you can pick bones over dense artwork without adding chains. Shown once the layer has bones.
Bends the skin through each joint as a rounded arc instead of a crisp corner crease, by blending each bone's end directions with its neighbours'. The same rule shapes rest and pose, so the rest position stays exact. On a layer inside a rigging folder this propagates to the folder's skeleton and to every member layer.
Where a new chain starts decides what it attaches to. Every existing bone's tail and head are candidates, and the nearest one within range wins:
- Snapping to a tail — a bone's tip — makes the new chain that bone's child. An arm drawn off a shoulder follows the shoulder.
- Snapping to a head makes the new chain that bone's sibling. A leg drawn at the hip hangs where the spine hangs, so bending the spine does not swing the leg.
The repair kit
Construction ships with its repair kit. Every one of these operations preserves the rest position of everything it is not explicitly changing — fixing one bone can never scramble the rest of the skeleton.
Adds a bone off the selected bone's tip. Then drag its end joint to aim it. The panel adds: "Adds a bone off the selected tip — then drag its end joint to aim it."
Re-hooks the selected bone to the joint it is sitting on.
Frees the selected bone into a root of its own. Disabled when it is already detached.
Splits the selected bone at its midpoint into two half-length bones. Children re-hang from the new
upper half and nothing moves. The new bone takes the original's name with a ·2 suffix.
Destructive; reads Delete bones with more than one selected. Children are re-parented to the grandparent without moving.
Destructive. Clears the skeleton.
The panel states the repair contract itself: "Wrong parent? Connect re-hooks the selected bone to the joint it sits on; Disconnect frees it. Nothing moves — only what follows what."
Dragging a joint handle repositions it. Moving a tail re-aims and re-lengthens its bone about its head, and each direct child's head follows the joint while its own tail stays put. Moving a head leaves the tail put and re-aims the bone. Everything further down the chain keeps its rest position exactly.
The panel reports the bone count, and the selection above the repair buttons as Selected: <name>. With bones but nothing selected it reads "Tap bones to select them for splitting or deleting."
Jiggle
Makes the selected bones lag and overshoot automatically during playback — tails, hair, a ponytail, a coat tail. At 0 the bones are rigid. Raising it both softens the pull back toward the keyed pose and carries more velocity from frame to frame, so low values settle quickly and high values swing loosely. Only rotation lags; position and scale are unaffected.
The slider reads the highest jiggle among the selected bones, and writing it sets every selected bone. The panel notes: "Jiggle makes these bones lag and overshoot automatically during playback (tails, hair). Deleting re-parents children without moving them."
Jiggle is a simulation, and it is deterministic: it only ever advances one frame at a time, so scrubbing backwards or jumping more than one frame re-simulates forward from frame 0, and the same frame always evaluates to the same result. Jiggly bones are stepped parents first, so a jiggling parent feeds its children's motion.
Pose
A normal bone is a normal bone. Dragging any bone — tip included — rotates just that bone, carrying its children along rigidly. Nothing else in the body moves. That is forward kinematics, and it is what posing does unless you ask for something else.
Reaching is opt-in, through a handle you place yourself, on the limb you want it on.
What you can drag
| On the canvas | What it does |
|---|---|
| A bone | Rotates that bone. Children follow; the rest of the body holds still. |
| A magenta ◆ handle | Runs an IK solve on its own chain — the limb reaches for your finger. |
| The green ⊕ ring under the character | Moves the whole body. |
| Empty canvas | Box- or lasso-selects bones. |
In a 3D shot the drags follow your view: orbit the canvas and the same drag carries the bone through depth.
IK handles
Select a single bone and the panel offers a handle for it.
Places a handle at the selected bone's tail. It is drawn as a magenta ◆, and it is hit-tested before the bones are, so grabbing one never rotates the bone underneath.
How far back up the chain this handle's solve reaches. 2 is an elbow and a forearm; raise it to pull the shoulder in as well. Each handle carries its own count, so a hand and a foot need not behave alike.
Deletes the handle. The bone poses as an ordinary bone again.
Lets the limb stretch beyond its natural reach instead of stopping at full extension. The stretch is measured against the bones' rest lengths, so repeated drags never compound, and it is applied to the first bone of the chain and inherited down it, so the limb stretches uniformly.
Three behaviours are structural and are not adjustable:
- The elbow keeps its bend side. The bend direction is read from the limb's current pose, so dragging a bent arm never flips its elbow to the other side.
- A reach stops at a branch. Climbing up the chain halts at any bone that carries more than one child, so a handle's chain can never walk into the spine.
- The reach eases into full extension rather than snapping straight, so there is no pop as the limb runs out of length. The softness is fixed.
Reaching is an input device for ordinary keys, not a rival system. The solve lands on the same bone rotation channels that dragging a bone writes, so playback replays plain bone keyframes and nothing re-solves at render time. Rotation keys are unwrapped against the channel's existing value so interpolation never takes the long way round a half-turn.
Posing one bone by number
Selecting a single bone adds sliders under Selected, for the times a drag is too coarse.
The selected bone's own rotation, and only its own — the rest of the body holds still. Z bends it in the picture plane; X and Y tilt it through depth. A 2D shot shows Z alone, because it has no depth to tilt into. Each slide is one undo step, and it auto-keys like any other pose change.
Moves this limb through depth so it sorts correctly against what it crosses — positive toward you to put an arm in front of the body, negative to tuck it behind. 3D shots only.
Keying a pose
Bone poses are keyframable on the ordinary transform channels, with the bone as the owner. A pose drag writes base values for every bone it solved, and auto-keys those bones whose rotation channel already exists.
Keys every bone at the playhead. Reads Key selected when bones are selected, and then keys only those. Disabled when the layer has no bones.
Removes the key at the playhead. Reads Remove key when bones are selected.
Copies the current pose.
Applies the copied pose. Disabled when nothing has been copied.
Returns the skeleton to its rest position.
The panel states the model: "Tap bones to select (tap again to deselect) — keys apply to the selection together; the timeline shows the selected bones' rows. The first key arms auto-key." Only selected bones appear in the Timeline's Bones section, which is what keeps a full character from flooding the tree.
Joint fixes
A joint fix is a correction that stores itself against a bend and reapplies itself whenever that bend recurs — a crease that only appears at 90° of elbow, fixed once.
Stores the current pin corrections against the current joint angle. Enabled only once pins have been dragged.
Destructive. Removes every stored fix. Disabled when there are none.
The panel gives the workflow: "Bend a joint, fix the crease by dragging pins (Puppet tool), then store — the fix applies itself with the bend from then on." In order:
Bend the joint
In Pose mode, bend the joint to the angle where the crease appears.
Fix the crease
Switch to the Puppet tool and drag pins until the artwork reads correctly.
Store it
Back in the Rig panel, tap Store fix. The header reports the running count as Joint fixes: <n>.
The fix is driven by how far the joint has bent from rest, measured relative to its parent bone — so moving the whole character never engages an elbow fix. It fades in from nothing at rest to full strength at the angle it was captured at, never overshoots past that, and stays silent on the opposite side: an elbow fixed at −90° contributes nothing when the arm bends the other way.
Weights
Weights decide which bone each part of the drawing follows. They are computed for you, and for most rigs you never touch them — but when the automatic answer is wrong at a joint, you can paint over it.
Automatic weights
Weights are shape-aware: they measure distance through the mesh, not straight across it. An arm lying beside the torso is close to the torso in the plane but far from it through the shape, so it never grabs torso pixels. The mesh's expansion past the silhouette is penalised heavily when a path tries to cross a gap, which is what stops one leg's bones reaching the other leg across the space between them, and each vertex keeps only the few strongest bones — a vertex holding a sliver of every nearby bone is exactly how posing a hand drags body strokes along.
Deformation is fitted as a rigid motion per vertex rather than a linear blend, so joints do not collapse, long bones carry their whole length, and the blend across a joint appears on its own.
A vertex may only blend bones that are its dominant bone's own parent, child or self. Without that rule, a four-way junction like a neck or a hip has no dominant bone, and a head vertex ends up carrying a slice of each arm — so rotating one limb tugs at parts of the body nowhere near it, and the limb's own weights are diluted enough that its artwork lags the bone at large angles.
Weights are built once, at bind time, against the skeleton at rest. Adding or removing bones rebinds them.
Weight painting
Switch the mode picker to Weights. Tap a bone to pick it, then paint over the artwork to bind what you paint to that bone. The artwork shows its rest pose throughout, and a heat overlay — blue through green to red — shows how strongly each part follows the bone you are painting.
The panel states it plainly: "Painting to 100% makes the area follow ONLY that bone; erasing hands it back to the others."
The paint brush's radius. A white ring on the canvas shows it.
How much each pass adds. Passes accumulate, so you can build influence up gradually.
Paints influence away from the selected bone, handing it back to the others.
Steps back and forward one paint stroke, on the rig's own history.
Throws away everything painted and returns to the computed weights. Destructive.
A tap selects; a drag paints
Tapping a bone selects it. Tapping anywhere that is not a bone paints a dab instead of clearing the selection, and a stroke has to travel a little way before it counts as painting — so a slightly shaky tap on a bone still selects rather than leaving a mark. Until a bone is selected the panel says Tap a bone to start.
Where the skeleton lives
There is no skin picker. Which kind of rig you get follows from where the active layer sits.
A layer on its own gets the skeleton on the layer, and the layer's own conforming mesh is skinned to it.
A layer inside a group gets a folder rig: one skeleton on the group, with every member layer binding its own mesh to that same skeleton. Each layer poses at its own depth, so a stack of drawings built at different depths keeps its parallax when the viewport orbits. The panel announces this with a banner: "Rigging folder “<name>” — one skeleton for all its layers (each keeps its depth)." The Bones section then appears under the group's row in the Timeline rather than the layer's.
Rig undo
While the Rig tool is active, the toolbar's Undo and Redo drive a rig-session history of their own, separate from stroke undo, and fall through to stroke undo once it is empty. Every rig operation is snapshotted before it runs, and rapid-fire changes — a slider, a drag — coalesce into one step. Leaving the tool clears this history: rig undo is scoped to the rigging session.