A hands-on Blender experiment · By GPTblender
I Turned a Floor Plan Into a Full 3D Model Using GPT-6 Astra in Blender — Here's Every Step
I used GPT-6 Astra and Blender to turn a floor plan into a furnished 3D home. Here are the results, the prompts, and how I got there.
See how the home was built.
See the finished renders, rotate the 3D model, or replay the build in eight stages.
Once it loads, drag to rotate the model
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Loading the build
This replay shows how the BlenderKit version was rebuilt in eight stages. The rendered images now use soft, warm lighting. You can compare it with the earlier versions below.
Download the model and see the project notes
Furniture sources and licenses- Layout follows the supplied four-bedroom, three-bathroom plan. Width 18 m and ceiling 2.9 m are design assumptions; dimensions need site verification.
- BlenderKit supplies six furniture asset types; asset-manifest.json records authors and licenses. All 40 image maps are packed in the original Blender file.
- The downloadable Blender file is the reviewed source. The browser companion uses lighter subdivision and portable PBR finishes; its lighting approximates Cycles.
- The replay rebuilds the BlenderKit design in eight stages. The four rendered images come from the original version; their file checksums and render logs are saved separately.
Each stage was rebuilt in Blender and saved as a 3D model. You can open the downloaded model in a 3D editor.
1. Get Blender ready.
Open a project folder in Codex and select GPT-6 Astra. Put your floor-plan image in that folder so Codex can find it and save its work in the same place. Then send this prompt:
install blender and blender cliBlender has a built-in command-line interface (CLI), which lets Codex run it by typing commands. Ask Codex to run blender --version and check that it returns a version number before you continue. I used Blender 5.2.1 LTS for this recording.
If you want to know how this works, the Blender manual explains how to run Python scripts without opening Blender’s interface.
2. Ask for a warm, modern interior.
Attach your floor-plan image, then send the prompt below. Here’s an English translation of the prompt I used for the BlenderKit version. It assumes BlenderKit is already installed.
Use the Blender CLI to turn this image into a warm, modern home interior. The furniture and lighting should look realistic, and the render should be good enough to present to the homeowner. Use furniture assets from BlenderKit; I have already installed it.I wanted something “good enough to present to the homeowner.” For the version above, I used furniture from BlenderKit and rendered the images with Cycles, Blender’s rendering engine. Here’s how it compares with my earlier attempts.
3. Three versions: the results and how long each took.
I tried three versions: a clay render, a textured render, and a version using BlenderKit assets. Here’s what each looked like and roughly how long it took. Each time is an estimate for that version; the three times shouldn’t be added together.
| Version | Approx. time | What I got |
|---|---|---|
| Clay render | 10 min | A clear room layout with basic furniture |
| Textured render | 50 min | Detailed wood grain, furniture and table settings |
| Render with BlenderKit assets | 30 min | A furnished home with BlenderKit furniture, textures, and lighting |
Clay render
Approx. time: 10 minutes.
The clay render is a plain, untextured render. It let me check the room layout, door and window openings, and furniture placement before working on materials and lighting.
Textured render
Approx. time: 50 minutes.
I added more detail to the wood textures, furniture, and table settings. The result still looked a little cartoon-like. This was an earlier attempt, before I tried BlenderKit.
Render with BlenderKit assets
Approx. time: 30 minutes.
For this version, I used ready-made furniture from BlenderKit, added materials and lighting, and rendered the images with Cycles. The view below shows all four bedrooms and the living and dining area. You can explore the model and see the build steps in the interactive replay.
What I’d watch out for next time
- Check the measurements. The overall width was estimated. A good-looking render doesn’t tell you whether the dimensions are right.
- Compare it with the floor plan. One earlier version added a terrace from the style reference. Check for additions that weren’t in your plan.
- More detail doesn’t always look more real. The extra objects and textures helped, but the textured version still looked a little cartoon-like.
- Compare similar views. The screenshots were taken from different angles, so they’re harder to compare directly.
The times above are rough estimates for each version. The replay and render logs cover only parts of the work, so their timings are different.
How the recorded timings compare
The eight-stage rebuild took 320.1 seconds, including saving a model at each stage. The original Cycles render commands took 804.7 seconds in total. These logs cover separate parts of the work; the 10-, 50-, and 30-minute estimates above cover the overall work on each version.
Token usage and a complete failed-attempt count were not recorded.
4. Frequently asked questions.
How do I turn a floor plan into a 3D model?
Give Codex a clear floor plan and at least one known measurement. Ask it to use Blender to build the walls and add doors and windows. Check the layout and dimensions before asking for furniture, materials, and lighting. Review the results along the way so you can catch mistakes early.
What app can I use to turn my floor plans into 3D models?
I used Blender for the 3D model and rendered images, with Codex running GPT-6 Astra to write and run the Blender scripts. You provide the floor plan, describe the look you want, and check the results. You can keep editing the model in Blender afterward.
More GPT-6 Astra Blender demos
See what other people have made with these tools in our architecture roundup.
Sources & project files
- Blender Manual: command-line arguments
- Blender Manual: rendering from the command line
- Blender Manual: glTF 2.0 export and materials
- The recorded eight-stage BlenderKit build
- The Python script used to record the build
The times are rough estimates from my own experiment. The clay and textured renders are earlier attempts. The BlenderKit image shows the version you can explore in the replay above.