spritecast

claude plugin marketplace add Sunghwan0112/spritecast
claude plugin install spritecast@spritecast

Then just ask: "Here's my character (hero.png). Make her walk in 8 directions." To try it free, with no key, ask Claude to "try SpriteCast".

An image model (OpenAI's, with your own key) does the drawing. The body, the motion, the angle and the shadow come from 3D - so every frame is the same person, and she actually walks.

Free and MIT. You pay OpenAI and Tripo directly; every paid step shows its cost and waits for your OK.

What you can make

A walk in 8 facings from one illustration, a shadow per frame	Actions: run, jump, slash - or any Mixamo clip
Pixel art, about 100 px tall, with things that are held and thrown	Four-legged animals, with no bought rig
Sitting on your props, the armrest in front of her worked out in 3D	Props at their real size, all on one floor

Things to ask for

• "Here's my character (hero.png). Make her walk in 8 directions."
• "Add a run and a jump. And a throw - here's a Mixamo clip (Throw.fbx); put a snowball in her hand."
• "Our game is pixel art. Make her walk and throw as pixel sprites, about 96 px tall."
• "Make her sit, and put her on this armchair."
• "Make a shopkeeper NPC, an old man in a brown cardigan, in four directions." (a posed figure: a description is enough)
• "Make an isometric bookshelf, 1.8 m tall, full of books, in the cozy style."
• "Here's a prop from my game (props/barrel.png). Make a matching crate in that style."

Why it works

An image model can't keep a body and a pose from one frame to the next. Asked for a walk in words, it gives eight nice drawings that don't walk - the left of the picture at the top, as it came out:

So SpriteCast never asks it to. 3D does the moving; the image model only redraws each rendered frame in your illustration's look. Every drawing is then fitted back onto its render and checked against it: a frame drawn in another pose is flagged and can be redrawn, never squeezed to fit. Props work the same way, with blocks at real size in place of the rig.

What you get from that:

• The angle and size are right. The solid props in the examples land on their guide at 95–99 % outline overlap; the plant, drawn loosely on purpose, at 87 %, and the dressed figures at 69–88 % (clothes and hair go past the plain mannequin). Walking characters are scored frame by frame (below). The camera and the scale are fixed, so props made at different times line up on one floor.
• Shadows that look right. One light shared by every prop, so every shadow falls the same way. Solid props cast the 3D guide's own shadow. Posed figures and plants cast a shadow in the drawing's own shape (the hood, the hair, the leaves), placed by the 3D model, so a foot or a pot's base starts its shadow where it stands. Walking characters cast their 3D body's own shadow, frame by frame. Not a painted blob, not a blocky mannequin.
• It checks itself. After drawing, the result is compared with its guide. If the model drew another angle, nothing is squeezed to fit: you get a warning, and Claude suggests a fix before drawing again.
• Your game's view and your style. 2:1 isometric, true isometric, 3/4 top-down, front or any angle; all four facings of one object; the bundled cozy style or one picture of your own.

Walking characters

Give it one illustration of a character (facing front, standing straight, no pose) and you get a walk in 8 facings (8 frames each) and 8 standing views, in that illustration's look. An image model can't keep a body and a pose from frame to frame, so the motion comes from 3D:

1. A turnaround is drawn from the illustration.
2. Tripo makes the 3D model from it, rigs it and gives it a walk and an idle.
3. The walk is rendered with the game's camera (free), each frame with the 3D body's own shadow, pressed flat onto the ground along the light.
4. The image model draws over the renders, 4 frames a call. The front is drawn first and every other facing follows it, so it stays the same person.
5. Every frame is fitted back onto its render, the head sizes steadied and the edges cleaned. You get strips, a shadow per frame (the feet touch it, a lifted foot casts its own) and an anchor.

$PYTHON skills/spritecast/scripts/charpipe.py turnaround hero.json --yes   # then 3d (model, rig, renders) and draw (then finish, preview by themselves)

All eight facings are drawn by default. A design that is the same on both sides can set "mirror": true to flip the west facings from the east ones (each keeping its own shadow), about $0.66 less.

Cost per character: about $2.2 (OpenAI; $1.5 with "mirror": true) and 75 Tripo credits ($0.75; an animal 30). Or bring your own rigged GLB ("rig_glb") and skip to render.

preview also makes walk-all.mp4 (every facing walking at once, with ffmpeg): the quickest way to see a head that grows and shrinks or a frame that jumps. Tripo sometimes sends a model back turned sideways or uncoloured; both are fixed for you. "modeler": "meshy" (and MESHY_API_KEY) has Meshy make the model instead (~30 Meshy credits); the rig is still Tripo's.

More options (several outfits, anchoring on the soles) and lessons: reference/character.md. The girl above is in examples/rain_girl: her illustration, turnaround, spec, strips, shadows, character.json and the sheet. She was made with Tripo alone: about $1.7 of drawing and 85 Tripo credits. Her rigged model is there too (rig.glb, with its walk, run, jump and slash, MIT like the rest of the repo), so you can try the whole 3D side with no keys and nothing paid: copy the folder, add "draw": false to the spec and run charpipe.py render rain_girl.json then finish - the strips, shadows and anchors come from the 3D model itself. Her spec also shows what "notes" is for: the 3D render had dark streaks down the raincoat's sides and inside the arms, and one line in notes ("no dark line, stripe or seam on it anywhere... leave them out") had them drawn out of every frame - a flaw in the model fixed in the drawing, not in 3D.

Four-legged animals

Tripo's rig for four-legged animals walks badly (no backbone, the shoulders hung off the neck), so an animal gets no bought rig. With "kind": "animal" the 3D model alone (Tripo, ~30 credits) is enough: its skeleton is found from the mesh (the feet, the back, the head, the tail, and which way it faces), it walk