Step-by-Step: Build a 3D Game Using Opus 5.5 / Astra + Tripo

This week, I used Opus 5.5 + Tripo + Blender to turn the interplanetary journey from The Little Prince into an explorable 3D game. After publishing, it garnered nearly 3 million views across the web.

Sac@Saccc_c·Oct 13Translated from ChineseShow originalSpending 16 days, I used Opus 5.5 to turn The Little Prince’s story into a 3D narrative game

Combining Tripo+Blender, Opus 5.5 transformed every planet in The Little Prince story into an explorable 3D scene

Hope everyone can support it—I’ll open-source the entire game later,Show more1.3K2.4K15K2.9M

Many friends really enjoyed the game. Behind the scenes, the bulk of the production work — from scene building and character creation to code development and debugging — was handled by AI.

So, I decided to open-source this production workflow, combining real-world examples and ready-to-use prompts to walk you through AI-assisted 3D game development, so you can start building the worlds you’ve imagined.

This article is divided into three parts:

1. Game development workflow and setup preparation
2. Scene construction
3. Character construction

1. Game Development Workflow and Setup Preparation

Game development workflow: Fable 5.1 handles the PRD, mapping out the game’s core scenes, characters, and storyline + Image 2.5 generates scene and character images + Tripo generates core 3D assets + Opus 5.5 builds the core code + Astra handles iterative optimization and bug fixes

Game tool configuration:

• Blender: Download the Blender CLI, used to optimize Tripo-generated 3D models and complete the overall 3D modeling of the game; install the paid Auto-Rig Pro plugin for character rigging and skinning, making it easy to create motion interactions.
• Unity: Install the Unity App (https://unity.com/) as the game engine to package scenes, characters, and interactive animations into a complete game; install the Unity CLI and add the Pipeline package to your project so Claude can directly operate on your Unity project via the official Unity MCP.

Next, this article will focus on scene construction and character creation.

2. Scene Construction

In short: Image 2.5 generates scene images → decompose 3D assets and generate them in Tripo → Opus 5.5 operates Blender + Unity for scene modeling

Detailed steps below 👇

(1) Use GPT Image 2.5 to generate scene reference images, turning ideas into clear visuals

Based on the game requirements gathered earlier, use Image 2.5 to generate scene reference images, establishing the overall art style, color palette, and the placement of key objects.

It’s recommended to first settle on a scene render you’re satisfied with, then build out other angles around it (especially for scenes with both interior and exterior). Top-down views are mainly used to explain the scene layout; angled side views supplement the height, shape, and depth relationships of objects. You can also directly generate a comprehensive view like this:

Reusable reference prompt:

Based on the uploaded scene reference image, help me generate a comprehensive reference image of this scene, including multi-angle views of the overall environment as well as close-up details.

(2) Have AI decompose the scene assets and identify which models need to be generated separately in Tripo

With the reference images ready, you can directly use AI to determine which assets in the scene should be generated separately in Tripo, and which can be built directly by Opus 5.5 in Blender/Unity.

Reference prompt:

I’m going to develop a game, and my tech stack is Tripo + Blender + Unity. Based on the scene reference image we generated above, help me analyze in depth which assets are suitable for generation with Tripo, and which are better suited for direct construction in Blender. Mark the assets that need Tripo generation directly on the image so I can confirm them.

For scene prop 3D assets in Tripo, it’s recommended to use the H3.1 model, which ensures high-precision detail in the assets.

(3) Use professional prompts to have Opus 5.5 operate Blender and Unity to begin modeling — the key to modeling is providing detailed reference images and iterating from multiple camera angles

After generating and exporting the 3D props that need individual creation in Tripo, hand these assets along with the scene reference images from step one to Opus 5.5, and have it operate Blender + Unity to build the overall environment, arranging props, and adjusting scale and positioning according to the reference images.

Once complete, review the scene from different angles — front, side, and so on — and iteratively adjust layout and details based on screenshot feedback.

Reference prompt:

Based on the uploaded multi-angle interior and exterior scene reference images and the generated Tripo 3D assets, perform a faithful reproduction matching the reference images. The result must achieve the same stunning quality and detail fidelity as the reference images. Once implementation is complete, dispatch an independent review agent to conduct a blind multi-angle review of the scene. If any discrepancies with the reference images are found, keep iterating until they are resolved.

3. Character Modeling

Image 2.5 generates character images → Tripo generates the character’s 3D model → Auto-Rig Pro plugin in Blender handles rigging and skinning → Mixamo animations are integrated → Complex interactions are fine-tuned in Blender (optional)

Here we’ll use the Little Prince’s design as a concrete example.

(1) Use Image 2.5 to generate multi-angle reference images of the character

Based on the character’s design and settings, first use Image 2.5 to generate T-pose four-view images of the Little Prince, making sure character details are consistent across all views.

(2) Use Tripo’s Smart Mesh P2.0 model to generate the 3D character asset

Smart Mesh P2.0 is a 3D generation model purpose-built for games and interactive content. Its standout feature is the ability to generate character meshes with controllable polygon counts that are easy to edit, making rigging and animation easier downstream.

In Tripo, select “Multi-View to 3D” and upload the four views in sequence. Set topology to default quads, push precision to the highest, select the P2.0 model, and start generation.

If the initial white model’s mesh looks clean and correct, you can click “Texture” to generate the model’s textures. If the mesh shape looks unreasonable, select “edit mesh” to regenerate specific areas.

(3) Use the Auto-Rig Pro plugin in Blender to automatically rig and skin the character

Once the plugin is configured, upload the character model directly to Claude and input the following prompt — one I’ve refined through repeated debugging — for efficient rigging and skinning 👇

Use Auto-Rig Pro to rig and skin the character, ensuring bone positions align with the character’s joints. After completion, test basic motions such as raising arms, bending legs, and turning around, and check for and fix any obvious deformation, stretching, or clipping issues.

(4) Download the required animation files from Mixamo and have Opus 5.5 adapt them to the character’s skeleton

Based on the game’s requirements, go to mixamo and search for the animations the Little Prince needs using relevant keywords, then download the corresponding FBX animation files.

After that, we can have Opus check whether each animation matches the Little Prince’s actual skeleton and complete the integration.

(5) Fine-tune special animations and contact details in Blender (for complex interactive motions)

For complex interactions like “the Little Prince picking up a watering can” that involve character-prop contact, Mixamo rarely provides a perfectly fitting animation. We can first select a close basic animation, then have Opus 5.5 iteratively fine-tune the details in Blender.

Reference prompt:

Please refer to the provided Mixamo animation, keep the applicable parts, and use Auto-Rig Pro’s arm IK controllers to adjust the arm pose. Combined with fine adjustments to finger gripping and watering can positioning, complete the watering-can-lifting motion. Ensure stable palm-to-handle contact, a natural lifting motion, and no clipping, grip detachment, or floating watering can.

Next week, I’ll open-source the full game code and more complete production details — stay tuned!

ps. If you’d like to try your own 3D creations with Tripo, you can sign up through my link and get 500 free credits: https://studio.tripo3d.ai/home?invite_code=H2DB1X&utm_source=X&utm_medium=kol&utm_campaign=kol_Saccc