RCP-compatible interface for Scan-to-BIM workflows (point cloud → IFC JSON)

### Checklist

- [x] I have searched for [similar issues](https://github.com/isl-org/Open3D/issues).
- [x] For Python issues, I have tested with the [latest development wheel](https://www.open3d.org/docs/latest/getting_started.html#development-version-pip).
- [x] I have checked the [release documentation](https://www.open3d.org/docs/release/) and the [latest documentation](https://www.open3d.org/docs/latest/) (for `main` branch).

### Proposed new feature or change

Feature Description

Hi,

I would like to propose an idea that could extend Open3D into the Scan-to-BIM ecosystem by enabling interoperability with BIM tools such as BonsaiBIM via an RCP (Remote Control Protocol) interface.

🚀 Proposal

Introduce a lightweight interface (or example module) that allows Open3D to act as an external processing agent:

* Input: point cloud data (E57 / RCP / generic point sets)
* Output: structured BIM data (IFC-like JSON)

🔧 Concept

Open3D would not need to implement full BIM logic, but rather:

1. Accept point cloud data via API / RCP-like interface
2. Perform geometry processing:
* Plane detection (RANSAC)
* Clustering
* Surface extraction
3. Classify basic building elements:
* Walls (vertical planes)
* Floors / slabs (horizontal planes)
* Terrain
4. Return structured output describing detected elements

JSON output
{
"elements": [
{
"type": "IfcWall",
"start": [0, 0, 0],
"end": [5, 0, 0],
"height": 3.0,
"thickness": 0.2
},
{
"type": "IfcSlab",
"outline": [[0,0,0],[5,0,0],[5,5,0],[0,5,0]],
"thickness": 0.3
}
]
}

🧠 Key Idea

Open3D acts as a geometry + detection engine, while BIM tools (e.g. BonsaiBIM) handle:

* IFC creation
* Parametric modeling
* Data management

🏗️ Benefits

* Expands Open3D use cases into AEC / BIM domain
* Enables Scan-to-BIM workflows without proprietary software
* Allows integration with AI/ML pipelines and agents
* Creates a bridge between point cloud processing and open BIM ecosystems

💡 Optional Scope

* Provide a reference implementation (Python example)
* Define a minimal schema for IFC-like JSON output
* Allow streaming or chunk-based processing for large point clouds

❓ Question

Would it be feasible for Open3D to expose or support such an interface (e.g. via Python API or example service), enabling integration with external BIM tools through a protocol like RCP?

🌍 Potential Impact

This capability could have a significant global impact, especially in the context of:

* Heritage preservation and restoration
* Reconstruction of historical buildings
* Digitization of cultural assets

Many heritage structures exist only as:

* damaged sites
* incomplete documentation
* irregular geometries difficult to model manually

By enabling a pipeline:

point cloud → structured BIM (IFC)

we unlock:

* Faster and more affordable reconstruction workflows
* Better documentation of cultural heritage
* Open and accessible tooling for smaller organizations and researchers
* Long-term digital preservation of historical assets

This is particularly important for:

* Post-disaster reconstruction
* Conservation of aging architecture
* Democratizing access to advanced reconstruction tools

Bonus : ifc has few easy classification ifcwall, ifcsite, ifcwindow, ifcduct, ifcpipe, ifcslab

### References

_No response_

### Additional information

_No response_