Chetan Ankola used GPT-6 Astra to generate a Three.js 3D experience: a creek scene with a log cabin, a stone bridge, flowers and grass, and rippling water glinting in sunlight. The experience runs and plays directly in the browser, and one commenter joked, "My laptop fan is actually flowing now." All 3D models were created in Blender.

The original tweet reads: This is running in a browser! can you believe it!

When a netizen asked how he pulled this off, he posted a breakdown of his costs. Total processing: 317.37M tokens, 158.42M for the main chat, 97.7% of input tokens pulled from cache, 1.28M output tokens (including inference). The estimated total cost is around $97 at standard rate, or $194 at accelerated rate. The models used were gpt-6.1-sol and gpt-6-astra.


He also shared his full prompt iteration process, condensing 24 rounds of human prompts into 14 key directional steps that he calls a "prompt arc". The steps include: import base assets (reuse existing water geometry), make the water the main focus (generate 5 core concepts), correct the scope (no endless ocean, just a small enclosed island), match materials (improve depth of field, lighting, and leaf colors), fix the cabin (check front and back faces), expose controls (restore sliders for water, sun, moon, elevation, etc.), check overall camera framing, restore performance (analyze and improve FPS), build the stone canal (run it under the cabin), refine the tunnel (deepen shadows, add moss), fix navigation (prevent the camera from clipping underground), add a sitting viewpoint on the cabin porch, add background music, and save the final night scene. Each step specifies exactly what needed fixing and how to adjust it.


One netizen commented: The browser needs more stuff like this, instead of just dashboards. Another specifically mentioned that the night water reflections are beautiful. The creator responded that it does feel really calming, and there's still a lot of room for improvement.

What makes this story interesting is that AI-generated 3D scenes are no longer science fiction. For under $100, an average person with enough patience can build a whole creek scene that runs in the browser. But the 14 steps of that prompt arc are the real barrier to entry. Knowing what needs to be fixed is far harder than telling AI what to generate.