Binding and weights
Connect a layer's points to your skeleton so the artwork deforms when the bones move.
A bone only moves what it is bound to. Binding connects individual points on a Shape or Mesh layer to one or more bones, each with its own weight, so a hinge like an elbow can hand off smoothly from one bone to the next. See Bones basics for building the skeleton itself.
The Bone Bind Tool does the binding. With Weight Paint off, it lets you pick a bone, select the points that should follow it, and bind or unbind them; turning Weight Paint on switches the same tool to hand-painting influence: see Weight painting.
Selecting a bone and points
Click within a few pixels of a bone to select it, or Shift+click to select several. Shift extends the selection only among bones of the same kind, so Static handles and deforming bones never mix in one selection: the same rule the Bone tool follows. Click a point on any editable Shape or Mesh layer to select it, or Shift+click to add more points to the selection. Dragging over empty space starts a marquee that only picks up points on layers already in your selection, so you can box-select safely without sweeping up a neighbouring shape.
| ShiftJ | Bone Bind Tool |
| Enter | Bind the selected points to the selected bone |
| U | Unbind the selected points from the selected bone |
A bound point defaults to a weight of 1.0 for that bone. Binding the same point to a second bone splits its influence between the two, which is what lets a knee or shoulder bend without a hard crease.
What stable point identity means
Every point on a Shape carries its own permanent identity that survives editing. Insert a point mid-segment, delete another, or reorder the path with the Node tool, and the bindings you already made stay attached to the same points. Celas Studio does not re-count positions and guess. This is what makes it safe to keep refining a drawing after it is rigged.
Auto Weight
Auto Weight replaces the bindings on the shapes you are working with with a smooth, distance-based falloff from every bone in the layer, up to four influencing bones per point. Run it with points selected to limit it to the shapes those points belong to. With nothing selected it works on the SELECTED LAYERS, not on the whole document, and it replaces whatever weights those layers already carry. It is the fastest way to get a plausible starting rig before you refine anything by hand.
The weight area
Weight Area, on the selected bone, recomputes only that one bone's influence as a soft Gaussian falloff out to the radius you set. It leaves every other bone's weights, hand-painted or automatic, untouched. Leave it at 0 and the radius follows the rig automatically, at roughly seven tenths of the average bone length. Raise or lower it to make one bone reach further or stay tighter than its neighbours.
Mirroring weights
Mirror Weights copies the weight of every bound point across to its mirror point on the opposite side of the canvas, matching bones by name: a bone named Arm.L feeds its weights to Arm.R, and vice versa. Name your bones with a matching .L / .R pair before relying on it.
Rigid layer binding
Link Layer, instead of binding individual points, makes a whole layer ride a single bone rigidly: it translates and rotates with that bone's motion from rest to its current pose, with no per-point falloff at all. Use it for a prop, an eye, or any layer that should move as one solid piece rather than deform. Unlink returns the layer to its own transform.