AI model that builds 3D · Kimi K3.1 Pro

Describe the 3D scene you want, and this AI runs the 3D software itself and hands it back animated

In the demos Moonshot AI released with Kimi K3.1 Pro early on October 24 (Korea time), you describe the 3D you want in words, and the model operates 3D programs like Blender, Unreal Engine, Godot, and CAD tools itself. It builds the parts, assembles the scene, then finishes the animation and rendering. We also collected what people outside the company built with it, and what they said, in the first three days after launch.

Oct 26, 2026·4 cases

Kimi.ai — Introducing Kimi K3.1 Pro (launch post, 2026-10-23, 3,930,011 views as of Oct 26)

Kimi.ai — K3.1 Pro 3D demo video (Blender, Unreal Engine, Godot, CAD), 2026-10-23

Kimi K3.1 Pro Tech Blog — where it's available, weights scheduled for release by Nov 4

When Moonshot AI released Kimi K3.1 Pro early on October 24 (Korea time), its launch post on X passed 3.93 million views by October 26. The video at the top is the 3D demo released with that post. In Blender, it builds up from a circular floor to a finished render of an indoor garden with a glass dome, a waterfall, plantings, and a monorail.

The Bugged Dev, a design engineer, gave the same piece of concept art to both Kimi and Claude Opus 5.5 and compared the results side by side. They said they were not sponsored, and wrote that they preferred Claude for the 3D modeling itself, but Kimi came fairly close. They added: "Kimi presented the overall scene better than Claude."

It's available now on the kimi.ai website, the Kimi app, the Kimi Work desktop app, the coding tool Kimi Code, and the API. The model weights are scheduled for release by November 4, so you can't download it and run it on your own machine yet. K3.1 Pro writes code that drives 3D programs: it builds the parts one by one, assembles the scene, and carries it through animation and rendering.

Reference 01Test run · Reddit user pzarevich, who builds the agent tool AgenC Core

A detailed text brief for a V8 engine became a 3D engine you can explode and see inside, in 31 minutes

pzarevich wrote a detailed request for a V8 engine built in Three.js and WebGL and ran it in AgenC Core with reasoning set to maximum. About 31 minutes later, Kimi finished on its own. The result was a 3D engine whose pistons, connecting rods, crankshaft, camshafts, and valves move together across all eight cylinders. It has start and stop, a slider that goes up to 4,000 RPM, and slow motion. A cutaway view makes the outer parts transparent so you can see inside, an exploded view spreads the parts apart, and you can put it back together. Click a part and its name appears. You can also walk around the workshop in first person to look at the engine. There is even a panel that shows the firing order.

pzarevich posted the result without edits and wrote that the engine geometry was built in code, not downloaded as a prebuilt model. AgenC Core called the model 39 times for this job and estimated the cost at $2.16. DeepSeek V4.1 Flash, given the same request, was cheaper at an estimated $0.86. But it did not finish on its own. When the run was stopped about 48 minutes in, after it passed a browser functionality check, it was still polishing the result.

pzarevich is a developer of AgenC Core, the tool used for this run. The V8 post does not mention that relationship; pzarevich disclosed it in a different post.

Preview image of the V8 engine result video pzarevich posted on Reddit — Preview of the result video (39 sec) pzarevich posted to r/kimi. Source: Reddit r/kimi

The exact request pzarevich sent to both Kimi and DeepSeek

Build a stunning, highly realistic, fully interactive 3D simulation of a **90-degree V8 combustion engine mounted on an industrial engine test stand**. Use Three.js and WebGL. Deliver a complete, runnable browser application. **THE OBJECT** A large, exceptionally detailed V8 engine positioned in the center of a clean, realistic engineering workshop. The engine must have: - Exactly 8 cylinders arranged in two banks of 4. - Visible pistons, connecting rods, crankshaft, camshafts and valves. - Detailed cylinder heads, intake manifold, exhaust headers, bolts, pipes and mechanical components. - Realistic metallic materials, machining details, rubber, steel and aluminum. - Accurate proportions and convincing mechanical construction. **REAL MECHANICAL ANIMATION** The engine must actually function as a synchronized mechanical simulation. - All 8 pistons reciprocate with realistic crankshaft-driven motion. - Connecting rods remain mechanically attached to the pistons and crankshaft. - Crankshaft rotates continuously while the engine runs. - Camshafts rotate at half the crankshaft speed. - Intake and exhaust valves open and close in a plausible four-stroke sequence. - Adjust RPM from 0 to 4,000 using an interactive slider. - Smoothly animate changes in engine speed. - Provide a slow-motion mode to inspect mechanical movement. **3D EXPLORATION** - WASD + mouse for first-person walking. - Mouse orbit mode for inspecting the engine. - Smooth zoom and camera movement. - Realistic perspective and scale. - Allow walking around the entire engine and inspecting it closely. **INTERACTIVE FEATURES** 1. START / STOP — start and stop engine operation. 2. RPM CONTROL — control engine speed. 3. CUTAWAY MODE — reveal the moving internal mechanism by making exterior components transparent. 4. EXPLODED VIEW — smoothly separate major engine components to show their construction. 5. ASSEMBLE — restore every component to its original position. 6. PART INSPECTION — click any major component to highlight it and display its name. 7. RESET CAMERA — restore the default viewing angle. **VISUAL QUALITY** Create a beautiful industrial visualization with: - Physically based materials. - High-quality reflections and shadows. - Realistic workshop lighting. - Detailed geometry with beveled edges. - Smooth animation and cinematic presentation. - A minimal, professional control interface. The engine must be actual interactive 3D geometry, not a flat image, video, or rotating fake model. **ENGINEERING AND CODE REQUIREMENTS** - Implement the geometry and mechanical relationships programmatically. - Do not depend on downloading a prebuilt complete engine model. - All controls must function. - All animated parts must stay correctly connected. - No placeholder interactions. - No fake loading screens or unfinished features. - Optimize performance for desktop browsers. - Provide all necessary files and instructions to run the project locally. **IMPORTANT** This is a benchmark of your ability to independently design, implement and deliver a sophisticated 3D application. Do not provide a tutorial or implementation plan instead of the application. Make reasonable decisions autonomously. Prioritize visual quality, mechanical correctness, functional interactions and stability equally. Deliver the best working implementation you can.

Swap the engine in the first line for the machine you want to see, then rewrite the parts and features lists below to fit it.

Reference 02Test run · The Bugged Dev, a design engineer learning Three.js (says it isn't sponsored) · X

Given one piece of concept art, it built a browser 3D scene of a frozen sea with drifting ice floes

The Bugged Dev gave Kimi K3.1 Pro and Claude Opus 5.5 the same job at the same time: turn a piece of concept art into a finished 3D environment. About an hour later, Kimi delivered a 3D scene that runs right in the browser. Ice floes drift across a reflective frozen sea, and lit windows glow warm between snow-covered fjords. The result is live at police-station.kimi.page.

For the same job, they wrote, Claude used 62% of the 5-hour usage limit on a $100 plan, while Kimi used 0.53% of the usage limit on the plan they were on (Vivace). Vivace isn't listed on Kimi's current pricing page, so we could not confirm that plan's price or limit period. That means the two numbers can't be compared on equal terms.

Reference 03Official demo · Moonshot AI API docs

In the official demo, it built a 3D robot arm with 2,317 parts and 268 cables in the browser

Moonshot AI's API docs say K3.1 Pro built a 3D robot arm model you can run in the browser. It includes an exploded view that pulls the parts apart, a transparent outer shell, and a cross section that slices it open to show the inside. The company says the model generated 2,317 parts and 268 moving cables in code and passed 55 browser tests.

Reference 04Official demo · Moonshot AI API docs

In the official demo, it built a jet engine with a spinning fan and shafts out of 2,100 solid pieces

This is the second demo in the same doc. K3.1 Pro drove the CAD program FreeCAD through Python to build a turbofan engine model. It includes the fan, a reduction gearbox, compressor, combustion chamber, turbine, and external plumbing, and the company says it is made of 2,100 solid pieces. According to the company, it shows the assembly steps and the exploded interior, with an animation of the fan and two shafts spinning at 2,780, 8,590, and 12,400 RPM respectively.

How people reacted

What people liked

“The visuals looked a bit better than what I got from Opus 5.5 surprisingly”
Posted after having Kimi K3.1 Pro make a 15-second promo video for Claude Code. They said it was not sponsored and wrote that they would still use Opus 5.5 more for everyday work.
Chris(@ChrisGPT) · Xx.com
“It wrote its own headless browser script to render seven test frames and check for console errors, which nobody asked it to do”
From a post about having it build a 28-second scene of a flying dragon in a single Three.js file. The author is the developer of Atomic Agent, an open-source agent that got access before launch.
GapNew4766 · Reddit r/kimireddit.com
“kimi k looks more realistic, better shadows, more details”
A comment looking at it side by side with the result from DeepSeek V4.1 Flash, which got the same V8 request.
WeatherJazzlike8376 · Reddit r/DeepSeekreddit.com
“now we are at a level where a 3d animation person would need days to makes sth similar (but well it would be more correct in detail maybe)”
A comment on the same V8 comparison post.
vogelvogelvogelvogel · Reddit r/DeepSeekreddit.com

What fell short

“The valve train on DeepSeek is way more visible and realistic. The exhaust headers too.”
A comment comparing it with the result from DeepSeek V4.1 Flash, which got the same V8 request.
TheUntergeek · Reddit r/DeepSeekreddit.com
“they both botched the cams”
A comment on the same V8 comparison post, about the results from both Kimi and DeepSeek V4.1 Flash.
OddWedding6914 · Reddit r/DeepSeekreddit.com
“33-rule brief: Opus passed 33/33; Kimi passed 31/33 but reported 33/33”
From a video comparing it with Opus 5.5 on 13 tasks in the same Claude Code setup, changing only the model name.
Prompt Engineering · YouTubeyoutube.com
“The model couldn't produce anything remotely close to what they showed in the release.”
Someone who subscribed to test it while building their own 3D game. They claimed Kimi's built-in 3D generation feature seems to call an outside service, but wrote that they could not confirm which company themselves.
Altruistic_Compote_9 · Reddit r/kimireddit.com
“the launch blog's "almost Opus" story does not hold up in real projects”
From a video that ran six tasks through PandaCode, an app the creator built, and ranked it 6th of 11 models.
AICodeKing · YouTubeyoutube.com
“No matter what style description or reference images I upload, it completely ignores them and spits out the same unplayable mess made of childish geometric shapes.”
From a post about trying to make their first game.
avelestat · Reddit r/kimireddit.com
“20% context used before it even does anything....”
From a post about trying it on a Unity project already in progress. They wrote that it couldn't fix a Chrome connection issue in six attempts, while Claude fixed it in one.
Wa1ker1 · Reddit r/kimireddit.com
“Same subscription on other providers (e.g. OpenAI/Anthropic with ultracode on) I get much more usage”
From a post saying the Kimi Ultra plan is hard to use for coding.
LessComplexity · Reddit r/kimireddit.com

How to start

Choose K3.1 Pro as the model in kimi.ai or the Kimi app, or pick K3.1 Pro with /model in the coding tool Kimi Code, then paste in the request below. To use it through the API, you need to top up at least $1 before this model is unlocked for your account.

Starter prompt
https://www.working-ref.com/en/reference/kimi-k3-1-pro-2026-10 has examples of people building working engines and 3D scenes with Kimi K3.1 Pro. Ask me about my interests, then suggest three 3D models based on them that I can run and take apart in the browser. When I pick one, start building it right away. If none of them fit, start with a moving machine model like the V8 engine in the first example.

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