Posing cut-outs with Pin Warp in Paint by Zaweba
Pin Warp in Paint by Zaweba lays a mesh over a layer and bends it around pins you place, with Rigid, Normal and Distort modes and pin depth controls.
Pin Warp in Paint by Zaweba is for bending an object as if it had joints. You place pins on it, drag some of them, and the rest of the shape follows naturally while the pinned parts stay where they are. It is the tool for lifting a cut-out arm a little, curling a tail, straightening a bent stem or giving a ribbon a new curve.
What happens under the hood
Edit > Pin Warp lays a triangle mesh over the opaque pixels of the layer. Transparent areas are left out, which is why Pin Warp works best on a cut-out on its own layer. When you move pins, an as-rigid-as-possible solver bends the mesh, and the pixels follow. As-rigid-as-possible means each small piece of the mesh tries to keep its own shape, so the bend spreads smoothly rather than stretching one spot.
Placing pins
Click to add a pin. Pins are anchors: anything pinned stays put unless you drag it. A good pattern is to pin the parts that must not move first, such as a shoulder and the body, then pin the part you want to move, such as a hand. Drag the hand pin and the arm bends between them.
Alt+click a pin to remove it. If the bend is spreading too far, add another pin to stop it. If it is too stiff, take a pin away.
Modes
There are three modes: Rigid, Normal and Distort.
Rigid keeps the shape at its stiffest, which suits limbs and solid things that should bend at a point rather than stretch. Normal is a balanced choice for most work. Distort allows more stretching, which can be useful for soft things like fabric and for creative effects, but can look rubbery on anything solid.
Density sets how fine the mesh is. A denser mesh follows small details better but is heavier to work with. Expansion grows the mesh beyond the edge of the pixels, which helps keep soft edges and fine hairs included in the bend. Show mesh draws the triangles so you can see what is happening; turn it off to judge the result.
Pin depth and rotation
When bent parts overlap, pin depth decides which part is in front, for example an arm crossing in front of the body rather than behind it. Pins can also have a fixed rotation, which stops the area round that pin from twisting as you move others. That is helpful for keeping a hand or a head facing the same way while you move the arm or neck.
A practical walk-through
Cut out the object onto its own layer. Make a copy of the layer, so you keep the original. Start Pin Warp on the copy. Choose Rigid for a limb. Pin the base, the joint and the end. Drag the end pin gently. Check the edges; if hair or a soft edge is being clipped, raise Expansion. When it looks right, apply it, then clean up any gaps left in the background where the object used to be, using the retouching tools.
Warp bends a whole layer smoothly with a grid. Fluid Warp pushes pixels with a brush. Free Transform changes size and angle. Pin Warp is the one for changing a pose, where you need parts to stay put while others move.
Things to avoid
Large bends on photographs tend to show stretched texture, so keep moves modest. Too many pins fight each other. And if you warp the only copy of a layer, there is no going back after you save, so work on a duplicate.
Pin Warp turns a fixed cut-out into something you can pose, and in Paint by Zaweba it is just an Edit menu away.
