Let an AI Build a World, Then Play It

An island, palms, a pier, a boat, a fishing hut, modeled in Blender by the AI; walking, casting, bait, catching, day and night, added one layer at a time ^{1 2}. A recipe for having an AI agent build a fishing game like that has been posted.

rewind02 wrote up how to build a game like this with Claude Opus 5.5, Blender and Unity 6 ³.

Build the island, play it, fix it

Here are the steps, in the poster's own words.

• Step 1: connect Claude Code to Unity and Blender through MCP [[C163]]
• Step 2: write a big brief covering the world, the mechanics, the UI and the mood, plus reference images [[C164]]
• Step 3: add a CLAUDE.md with your rules, and design docs as the single source of truth, so Opus never has to guess [[C165]]
• Step 4: split the work among subagents (design, modeling, textures, and a reviewer that only looks and approves) [[C166]]
• Step 5: Opus models the assets in Blender: the island, palms, pier, boat and fishing hut [[C167]]
• Step 6: it builds a greybox in Unity first, plays it, fixes it, and repeats [[C168]]
• Step 7: add mechanics a layer at a time: walking, casting, bait, catching, day and night [[C169]]
• Step 8: you watch and give feedback with a reason, such as "too dark at dusk" or "cut the water stripes" [[C170]]

What stands out is the order. The trick, the poster writes, is preparing everything before Opus writes a single line ⁴. Don't ask for the game first. Get the brief and the source of truth in place, then let the building hand move.

Then come the rules that make it work. The agent that builds is never the one that approves, and every fix gets written into a file so the next project starts smarter ⁵. It points the same way as step 8, where feedback comes with a reason ⁶.

And start small. A fishing game, the poster says, is the perfect first project ⁷.

From photos and a floor plan to a 3D Airbnb

The raw material for a world doesn't have to be imagined. SimbasJungles writes (in Portuguese) that they sent some base photos and a 2D floor plan, plus references from Pinterest, and asked for a 3D world built with Blender and Unreal Engine 5 ⁸. The post opens "Eu modelei meu Airbnb inteiro com Opus 5.5," which translates as: I modeled my whole Airbnb with Opus 5.5 ⁹.

Photos and a floor plan were the raw material for the request ⁸. It runs the opposite way from an imagined island: starting from something real.

Open a browser tab, and you're in the world

Some examples put the world in a browser with three.js. A quick tour.

anxuanng writes that Opus 5.5 built every asset in Blender and this whole three.js scene in 76 minutes, with no hand edits ¹⁰. The timing and the lack of edits are the creator's own claims.

NFT_Chen (in a Chinese-language post) writes that a rainy-night convenience store game came out of 3 sentences of prompt to Opus 5.5 plus three.js ¹¹. The creator points to the inside and outside of a Japanese convenience store on a rainy night, reflections in puddles, streaks of rain, and the contrast between warm light and cold blue ¹². A girl with long hair runs holding a clear umbrella, the post adds ¹³.

ai_growth_avii writes that Opus 5.5 made a drone racing game, using just three.js, in the browser ¹⁴.

akakuma0219's "Yuuyake Roji" (Sunset Alley) is a miniature world that takes in an illustration and moves with simple animation, according to its creator, who wrote in Japanese ¹⁵. The illustration prompt was only a single line, which translates as "a Showa-era downtown, in a watercolor anime illustration style," and Opus 5.5 made the result, animation included, the creator writes ¹⁶. One line of prompt in, a miniature world out.

chetanankola's "Cozy creek" is a three.js 3D experience of a creek. The creator says it was made with GPT 6 Astra and runs in a browser ¹⁷, and that everything was made in Blender ¹⁸.

Blender for the assets, three.js to put them in a browser. That pairing came up back to back, which caught our eye ^{10 18}.

If you want to do it at your own desk

First, a map of what is local and what is cloud.

For Opus 5.5, Anthropic lists the Claude Platform and Amazon Web Services as where it is available ¹⁹. Claude Code's CLI runs on your machine, but the model needs an internet connection ²⁰. Claude Code does ship a win32-arm64 build ²¹.

The tools that build the world, such as Unity and Blender, are on the local side.

• The Unity 6 editor lists Windows 11 on Arm64 in its official system requirements [[F126]]. It is supported on workstations and laptops running without emulation [[F128]]. A free version, Unity Personal, is available [[F147]].
• Blender's download page says it is compatible with Windows on Arm [[F57]].
• three.js is released under the MIT License [[F130]].

Here is what NVIDIA says about RTX Spark. On 3D scenes, its product page says up to 128 GB of unified memory handles 3D scenes up to 90 GB, and OptiX and DLSS keep the ray-traced viewport moving ²². On agents, NVIDIA's blog says RTX Spark's 1 petaflop of AI compute and 128GB of unified memory can meet the computing demand of on-device agents ²³. For games, NVIDIA says gamers can run AAA games at 1440p over 100 frames per second with DLSS 5, Reflex and G-SYNC ²⁴.

Some of it is still ahead. According to NVIDIA, Blender is adding DLSS 4.5 Ray Reconstruction, arriving this fall with RTX Spark ²⁵. NVIDIA's Japanese blog says it is planned for Blender 5.3 ²⁶. That is a plan, not a shipping feature.

None of the examples above is described as made on an RTX Spark machine. If you want to run Unity, Blender or Unreal Engine on one, check each tool's official documentation for supported environments first.

Some RTX Spark machines.

A game only shows you what to fix when you play it, which is exactly the loop of playing and fixing in the steps above ²⁷. If you're checking casting or running, a game controller in hand may make that easier.

And for orbiting around an island or a hut in Blender, there are devices made for moving the viewport.

Read next

For more on the Blender side, see the article on letting an AI agent handle Blender.

And for a desk where things keep happening after you stop, see the article on videos that pile up while you sleep.