Port a Three.js game to Unity and keep the hand-tuned physics

What you end up with

Ask the agent to read your code before it picks a framework, and say what must not change (here, the driving feel).

What you get

• A plain-language summary of the workflow
• A fill-in prompt template
• What to watch out for
• A link to the original source

Who it is for

Builders who already use AI agents and want a proven workflow they can copy into their own project.

Works with

Solid chips: the agent is named in this listing's own tools list. Dashed chip: Plain Markdown, so it also pastes into other agents such as Grok Bot, Hermes, OpenClaw or Muse. We list those as compatible by format only, not as tested.

Tools needed

Cost to run: Free with the agent plan you already use.
Time to result: One working session

How it works

1. Name the part of your game whose feel must not change and point the ag

   Name the part of your game whose feel must not change and point the agent at it

   Expected: Done before you move to the next step.

2. Ask the agent to compare candidate engines against that code before in

   Ask the agent to compare candidate engines against that code before installing anything

   Expected: Done before you move to the next step.

3. Port the core logic first and test it side by side with the original

   Port the core logic first and test it side by side with the original

   Expected: Done before you move to the next step.

4. Do the UI as a separate pass from a concept image

   Do the UI as a separate pass from a concept image

   Expected: Done before you move to the next step.

5. Keep the old build so you can compare feel on the same input

   Keep the old build so you can compare feel on the same input

   Expected: Done before you move to the next step.

Sample prompt from the pack

Apply this workflow to [your project]:
1. Name the part of your game whose feel must not change and point the agent at it
2. Ask the agent to compare candidate engines against that code before installing anything
3. Port the core logic first and test it side by side with the original
4. Do the UI as a separate pass from a concept image
5. Keep the old build so you can compare feel on the same input
Stop and ask me before anything irreversible: deploys, payments, sends or deletes.

Free preview of the file

# Port a Three.js game to Unity and keep the hand-tuned physics

PaperChase agent use case (free feed entry), version 1.0. Source: [@froessell on X](https://x.com/froessell/status/2114310224391655453), 2026-10-25.

## What they did

The builder wanted Drift Lane on iOS and Android. They asked Claude Code to choose between two racing engines from the Unity Asset Store. After reading the existing code, it recommended skipping both, because the handling came from about 170 lines of tuned physics that neither engine would reproduce. It ported that code directly. For the UI, a ChatGPT concept image went to Claude Design for a first draft, then Claude Code rebuilt the screens in Unity.

## Worth knowing

Ask the agent to read your code before it picks a framework, and say what must not change (here, the driving feel). A direct port of a small, tuned core often beats adopting a big engine. The game is still in progress.

Worth knowing

• Ask the agent to read your code before it picks a framework, and say what must not change (here, the driving feel). A direct port of a small, tuned core often beats adopting a big engine. The game is still in progress.
• Figures are as reported by the original author and were not re-measured by us.

Details

Version 1.0 · Updated Oct 26, 2026 · Markdown version of this page
License: Personal and commercial use. Credit the original source when you share the workflow. Download terms

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