Bone tool and rigging

Build a character rig with bones

Switch to Animate mode (Ctrl+3). The Skeleton and bone tools live there specifically, not in Prototype mode with the general shape tools.

Placing your first bone. Mouse down sets the bone's origin, drag out, and mouse up sets its endpoint — one explicit, two-point bone per drag. Click on an element that isn't part of a skeleton yet while placing a bone, and that element attaches to the new bone automatically. Laying a bone directly over a piece of art is itself a form of binding it, not just a visual overlap.

Building a chain. Click on the end of an existing bone before dragging out the next one, and the new bone becomes a child of it; that's how a chain (an upper arm, then a forearm, then a hand) gets built: one drag at a time, each one continuing from the last.

Bind artwork to a skeleton

The automatic attachment that happens while placing bones covers the simple case, but Formo also has a deliberate binding workflow for everything that isn't: attaching multiple shapes to a bone at once, re-binding art after you've redrawn it, or binding artwork the bones don't happen to physically overlap.

Bind Selected. With one or more shapes selected alongside a rig, this button binds all of them to the skeleton in one action. Regardless of how many shapes you selected, it's a single undo entry, not one per shape.

Unbind. With specific shapes selected, this removes just their bindings. With only the rig itself selected and nothing else, it clears every binding on the whole skeleton at once.

Bind is membership, not parenthood. Binding a shape to a bone doesn't change where that shape sits in your layers tree; it's a separate relationship specifically about deformation influence, not structural nesting. A bound shape can still live wherever it makes sense in your document's hierarchy.

Influence shows up in the panel as a read-only readout, not something you type a number into directly; it reflects a radius derived from the bone itself, telling you how far that bone's deformation effect reaches into nearby geometry.

Set the rest pose and bone influence

Rest pose. A dedicated action that captures the skeleton's current pose as its neutral baseline — the pose every deformation is calculated relative to. Setting this deliberately, once your rig is built but before you start posing it, is what keeps mesh deformation reading correctly rather than deforming relative to an accidental starting pose.

Use FK and IK to pose characters

Once a chain exists, how you drag a bone determines whether you're posing it with forward kinematics (FK) or inverse kinematics (IK), and unlike many rigging tools, this isn't a separate mode you switch into, it's determined by which modifier key you hold while dragging:

- Plain drag (FK, "world" variant): the bone you grab rotates, and its direct children counter-rotate to keep their own world-space orientation unchanged. The joint you're touching moves; what's attached past it doesn't visually follow along.

- Alt + drag (FK, "relative" variant): children do follow the parent's rotation this time — the more familiar, classic FK feel, where rotating a shoulder swings the whole arm with it.

- Shift + drag (IK): the bone you click becomes the effector; it doesn't rotate itself. Instead, its parent and grandparent rotate so the effector's own pivot point reaches wherever you drag your cursor. This needs at least two bone ancestors above the one you're dragging (a three-bone chain minimum) to solve, using a direct analytical two-bone solution rather than an iterative approximation: the math resolves the pose in one step rather than converging toward it over several.

- Shift + Alt + drag: IK, with the effector's own world-rotation additionally preserved as it's dragged.

- Ctrl + drag (chain extension): rotates from the grandparent's pivot instead of the clicked bone's, so the entire limb swings as one rigid unit rather than bending at a joint partway along it.

You can change your mind mid-drag: releasing or pressing Shift/Alt partway through a drag re-baselines smoothly from the pose at that exact instant, rather than jumping to whatever that modifier combination would have produced from scratch.

Set persistent IK targets

An IK solve isn't necessarily a one-off; a target can be set up to persist and keep solving continuously as the rest of the rig moves, rather than only resolving at the instant you drag. This is what lets an IK-driven foot, for example, stay planted convincingly as the rest of the body above it continues animating, rather than needing to be re-dragged into place on every single frame.

This is also exactly where the "early feature" caveat matters most. Five distinct modifier-key combinations driving fundamentally different solves is a lot to hold in your hand while also focusing on getting a pose right. Expect this to feel like the least discoverable, most engineering-flavored corner of Formo's animation tools today.

Deform meshes with bones

Beyond rigid bone rotation, a shape's mesh can deform smoothly as its bones move — a bicep bulging through an elbow bend, rather than two flat rigid pieces rotating around a hinge. Formo's own vocabulary for this is Deform, Influence, and Rest pose, the three concepts that together define how convincingly a mesh bends around its skeleton.

Use automatic weighting

Formo can generate starting weights automatically — how much influence each bone has over each part of the mesh — rather than requiring you to hand-paint every weight from a blank slate. A weight visualization shows which bone is influencing a given area of the mesh by color, so you can see the weighting before you commit to how it deforms, rather than discovering it only once you start posing.