Building a 3D Flight Scene with Sonnet in Cursor, three.js and 3D Models

Melvin Vivas · X video post · 2026-09-07 · 0:59 · 881 views · Open on X

Topics: AI Dev Tools & Productivity, Portfolio Projects · Level: beginner

Summary

Melvin Vivas shares a demo video (no narration) of a 3D plane-over-terrain scene. He built it in March 2025 using Claude Sonnet inside Cursor, with downloaded 3D models of the plane and terrain rendered in three.js. He thinks a newer agent ("Astra") could now rebuild it end to end using Blender and three.js, and that he would only need Codex Pro to do it.

Key points

• The demo was built in March 2025 by AI-assisted coding with Claude Sonnet inside the Cursor editor.
• He did not generate the 3D assets. He downloaded ready-made 3D models of the plane and the terrain.
• three.js was the rendering library for the browser-based 3D scene.
• His workflow: get the assets, then have the coding assistant write the three.js scene that loads and animates them.
• He thinks current agents (he names 'Astra') could now handle the asset side too by driving Blender alongside three.js.
• He says recreating the project today would only need a Codex Pro subscription, so the setup is getting simpler.
• The video has no speech, so all the detail comes from the caption.

Resources mentioned

• Claude Sonnet · tool · anthropic.com · check price
  Anthropic's mid-tier Claude model, widely used for AI-assisted coding.
• Cursor · tool · x.com · free · recommended by both Bashiri Smith & Melvin Vivas
  AI-native code editor (VS Code with AI built in).
  Also in: GLM 5.3 and GLM 5.3 Flash now in Cursor (Melvin Vivas on X · notes), Grok Bot Can Now Hand Off Coding Tasks to Cursor (Melvin Vivas on X · notes), Why Plan Mode Still Matters in AI Coding Assistants (Codex, Claude, Cursor) (Melvin Vivas on X · notes), Why Plan Mode Still Matters in AI Coding Agents (Codex, Claude, Cursor) (Melvin Vivas on X · notes) and 121 more
• Three.js · tool · x.com · free
  JavaScript 3D graphics library whose browser-rendered scenes can become video frames.
  Also in: Vibe-Coding a 3D Human Anatomy App with Three.js and GPT 5.6 (Melvin Vivas on X · notes), Building a Three.js Scene with Claude Opus 5 in Claude Desktop (Melvin Vivas on X · notes), HyperFrames: Let Coding Agents Turn HTML into MP4 Videos (Melvin Vivas on X · notes), GLM-5.1 vs Claude Code (Opus 4.6): One-Shot Three.js Racing Game Eval (Melvin Vivas on X · notes)
• Blender · tool · blender.org · free
  Free, open-source 3D creation software. In the demo the agent opens it to turn a drawing into a 3D model.
  Also in: Drive Blender from a Coding Agent via Headless Python Scripts (Melvin Vivas on X · notes), GPT-6 Astra Demo: One Agent Juggling Many Computer Tasks (Melvin Vivas on X · notes), ComfyUI Raises $30M: Open-Source Visual AI Pipelines Move into Production (Melvin Vivas on X · notes)
• GPT-6 Astra · tool · openai.com · paid
  The model announced in the quoted launch post, pitched as the developer's most capable model for work, coding, science and cybersecurity, and able to operate a computer.
  Also in: Customizing Your Coding Setup with Pi Coding Agent Extensions (Melvin Vivas on X · notes), Pi Agent Council: Ask Multiple LLMs in Parallel and Compare Their Advice (Melvin Vivas on X · notes), Use GPT-6.1 Sol by Default, Save Astra for Emergencies (Melvin Vivas on X · notes), Dots in ChatGPT: always-on AI agents that you hand responsibilities to (Melvin Vivas on X · notes) and 49 more
• OpenAI Codex · tool · openai.com · paid
  OpenAI's coding agent. In the diagram it writes code, fixes review findings and drives the build loop. The creator also used it to make this video.
  Also in: An agent bot that installs and drives Codex on its own (Melvin Vivas on X · notes), Asking a Coder bot to install Codex (Melvin Vivas on X · notes), Sign in with ChatGPT: Setting Usage Limits for Each App (Melvin Vivas on X · notes), Codex Cloud Environments Must Be Saved & Published Before Use (Melvin Vivas on X · notes) and 240 more

Try this

• Build a browser 3D flight scene: download free plane and terrain 3D models and use an AI coding assistant (e.g. Sonnet in Cursor) to write the three.js code that loads and animates them.
• Recreate the same scene with an agent that also creates or edits the assets in Blender, then exports them to three.js.