3dicon

3dicon

Generate a still, animate it into a seamless loop, key the background out properly, and encode it as an animated WebP with true soft alpha — the format expo-image, Chrome and Safari all render natively, with no Lottie conversion and no new native dependency.

Before anything

1. pip install -r requirements.txt (or uv pip install -r requirements.txt).
2. cp .env.example .env and fill in the keys for the backend you want.
3. ffmpeg must be on PATH.

Check the keys are present before running — animate costs money, and a run that dies halfway has already spent it.

Always stop after the still

One still, then ask. Never generate several takes to choose from, and never run through to the animation without the user seeing the art first.

1. Generate exactly ONE still.
2. Show it to the user and ask plainly whether they are happy with the

static design before anything else happens.

1. Only on a yes, animate it.

Why this is a hard rule, not a nicety: the still is 13 cents and the full run is 48 cents and four minutes, and every later stage inherits the still's object, colour and weight. Animating art the user has not approved means paying twice. run therefore stops after the still on purpose.

If they are not happy, adjust the prompt and generate one replacement — not a grid of options. Variants exist behind --variants but are off by default and should stay that way unless the user asks to compare.

How to report back

Keep the chat almost empty. The user is looking at an image, not reading a report — everything they need is either in the picture or in one line under it.

After the still, say only this, then stop and wait:

> Still ready. > (show the image) > Happy with it, or change something?

Do not explain the prompt, list what you did, or describe the image back to them. They can see it.

Then propose the motion and stop again. Do not animate on the strength of the still being approved — the motion is the second decision and it is the one that costs four minutes. Propose exactly one:

> Motion — (one plain sentence: what actually happens, in physical terms) > event · lively · --emit > > Agree, or describe the motion you want?

One sentence and the flags. No reasoning, no alternatives, no explanation of what the flags mean.

If they describe their own motion, translate it. They will use ordinary words; your job is to turn those into the flags and one physical sentence, not to pass their phrasing through. Work out:

• what does this object do when left alone? → --strategy
• how much should the object itself move? → --energy
• would the action throw something off? → --emit
• what literally happens to the material? → --motion

Then show the translated proposal in the same format and confirm before running. If what they asked for is not supported — a camera move, something entering the frame, the object travelling away — say so in one line and offer the nearest thing that is.

animate --dry-run composes the full prompt and spends nothing. Use it if you need to check what the flags expand to; do not paste the result into the chat.

After the animation, one line of numbers and the file:

> Done — flame.webp · 857 KB · 122f @ 24fps > (show the contact sheet)

If verify fails, one line on what failed and one on what you propose:

> Motion too weak — step 0.9, needs 1.0. > Retry as event with --emit?

Never paste raw CLI output, stage-by-stage progress, the composed motion prompt, or a summary of the pipeline. If a stage succeeds, its output is the file — say the filename and move on. Save the detail for when something breaks and the user has to choose what to do next.

The pipeline

python -m iconloop --out out still   --prompt "a 3D stopwatch, sage green and cream, soft matte plastic"
python -m iconloop --out out animate --motion "the stopwatch rocks gently while its hand sweeps clockwise"
python -m iconloop --out out matte
python -m iconloop --out out encode  --sweep
python -m iconloop --out out encode  --size 288 --name timer
python -m iconloop --out out verify

run is just still plus the reminder to stop and ask. The stages are separate because each one is a place to look before spending the next thing.

Choosing the motion

Before animating, answer one question: what does this object do when left alone? The answer picks the strategy, and picking it wrong is the main cause of a dull or generic result.

| answer | strategy | what you get | |---|---|---| | It moves by itself — flows, burns, breathes, ticks | native | continuous motion from its own physics | | Nothing. It is inert until used | event | it performs its function once, then rests | | Nothing, but part of it is loose, hinged or light | part | the body anchors, one small piece moves | | Nothing, and it has no moving parts at all | surface | light or material travels across a fixed form |

Most objects people ask for are inert. Asking an inert object to move naturally is what produces a turntable spin or an aimless bob — it has no natural motion, so the model supplies a generic one. Reach for event first unless the thing genuinely moves on its own.

Add --emit when the action would realistically throw something off — a fragment, a droplet, a spark, a glint. For an inert object that emission is often the entire reason the animation reads at icon size.

event and part also permit the object to be temporarily altered — something removed, opened, split, filled — as long as it returns to its opening state so the loop closes. Without that permission an object can only ever jiggle.

How much it moves

--energy decides whether the object itself moves, separately from what it is doing. Body motion is not the enemy — aimless body motion is. A squash, a recoil, a quick shake, an anticipation before an action: that is most of the vocabulary that makes something feel alive, and forbidding it to avoid a turntable spin throws away the whole language.

| energy | the object | |---|---| | still | holds completely rigid | | calm | leans, settles, breathes a little | | lively | squashes, tilts, recoils, shakes, springs back | | playful | anticipates, overshoots, wobbles, hops in place |

Defaults follow the strategy — native and event get lively, part gets calm, surface gets still — and an explicit --energy always wins. If a result feels lifeless, raise it before changing anything else.

Only two things stay forbidden at every level: rotating as a whole, and drifting. Everything else is available.

Small and many beats large and one. A single big motion of the whole object is the obvious choice and the worst one: it risks the frame edge, it reads as generic, and it says nothing about what the object is. Motion distributed over the object's own details cannot leave the frame and is specific to that object by construction. Where it has several of the same element, they must move out of step with each other — unison is the loudest tell that something was animated rather than observed.

Everything that goes out comes back. Anything that extends, rises, spreads or is thrown off must retract, settle, be reabsorbed or fade. Stated as physics rather than as a boundary, because a boundary is something the model can cross without noticing — and a round trip is what the seamless loop needs anyway.

Animate the effect, not its cause. The commonest way a good result still comes out wrong: the model reaches for whatever would normally cause the motion, and that cause is usually the object being moved by something. The physics ends up correct and the icon ends up bobbing, because at icon size the cause is invisible and only the displacement reads. Describe the effect by itself and let gravity, heat, air, tension or the object's own forces drive it.

Then say in --motion what the specific action is, in plain physical language. Describe what happens to the material, not what the animation should feel like.

Rules that matter

Resolution is the quality lever, not the WebP quality setting. Measured on one icon: quality 50 to 90 cut colour error from 2.96 to 1.84 out of 255 and added 500KB — nothing you can see. The visible loss is the downscale from a 1440px render. Defaults are now a 512px master and a 384px output; raise --size before you touch --quality, and never above the master, which only upscales.

Encode at the source frame rate. Kling returns 24fps. Sampling down to 8fps to hit a size target is the single most common way to ruin one of these — it produces judder that looks like a bad render, bad matting, or a bad player, and is none of those. --sweep prints what each rate actually costs; choose with the numbers in front of you. Smooth, slow motion suffers worst, so the icons that most want animating are the ones a low frame rate hurts most.

The last frame is set to the first frame. That is what makes the model return to its opening pose and the loop close. It is handled for you in kling.py on both backends; do not remove it and try to cross-fade instead.

Motion runs through OpenRouter on Seedance 2.0 by default. --model picks another — Seedance 2.5, Veo 3.1, Hailuo 3 and Wan 2.7 all accept a first and last frame. Not Kling 3.0: it caps prompts at 2500 characters and the composed motion clause is longer, so it rejects the request outright. --via replicate is the fallback and stops at Kling 2.5.

The backing colour is load-bearing. The still is flattened onto a known mid-grey before it is sent. Because the colour is known exactly, the matte stage solves C = (F - (1-a)*BG)/a for the true foreground rather than estimating it — measured, that cut edge colour error from 26.9 to 15.9. Do not switch it to chroma-key green or magenta: those spill onto glossy edges.

Believe the verifier, not the contact sheet. A render can look animated in stills and be almost entirely static — it has happened, 1 moving frame out of

1. verify measures motion inside the object and exits non-zero. If it says

the render is static, re-prompt; do not encode it.

Never temporally smooth alpha. It seems like the obvious anti-flicker move and it smears a ghost ring around anything that moves.

What it cannot do

See docs/limitations.md. The short version: the soft contact shadow does not survive matting, file size scales with frame count, transparent MP4 needs an x265 build most distros do not ship, and an animated WebP cannot honour reduced-motion — ship the still alongside it.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: samyost1
• Source: samyost1/3dicon
• License: MIT

Install and usage instructions live in the source repository linked above.