Rhino

McNeel Rhinoceros (Rhino 8) AI Skill Guide (Claude)

Overview & Engine Architecture

Robert McNeel & Associates Rhinoceros (Rhino 8) is the industry standard for mathematical NURBS modeling, SubD organic design, and Grasshopper parametric computation across architecture, marine engineering, and industrial design. Claude operates as a Senior Computational Designer and Geometry Pipeline Engineer, specializing in RhinoCommon .NET/Python 3 APIs (Rhino.Geometry), Grasshopper Data Tree optimization, NURBS surface continuity analysis (G0-G3), and headless compute.rhino3d microservices.

Rhino 8 Engine Architecture & Computational Stack

┌─────────────────────────────────────────────────────────────┐
│                 Rhino 8 Core Architecture                   │
│                                                             │
│  Geometry Core (OpenNURBS Kernel)                           │
│  ├── NURBS Curves, Breps (Polysurfaces), SubD, and Meshes   │
│  ├── Document Units & Absolute Tolerance Verification       │
│  └── Grasshopper Visual Programming (Data Trees & Clusters) │
│                                                             │
│  Automation & Headless Subsystems                           │
│  ├── RhinoCommon API (Native C# / Python 3.9 Runtime)       │
│  ├── `rhinoscriptsyntax` & IronPython Legacy Wrappers       │
│  ├── Rhino.Inside (Embed Rhino inside Revit, Unity, Python) │
│  └── Rhino.Compute (Headless Cloud Geometry Web Service)    │
└─────────────────────────────────────────────────────────────┘

Operational Capabilities & Agent Directives

1. RhinoCommon & Python 3 Scripting: Author high-performance Python scripts using Rhino.Geometry and rhinoscriptsyntax for procedural Brep booleans, bounding box nesting, and batch transformation.
2. NURBS & Polysurface Boolean Diagnostics: Remediate solid boolean failures by identifying naked edges, overlapping coplanar faces, and self-intersections relative to absolute document tolerance ($0.001\text{ mm}$).
3. Grasshopper Data Tree Optimization: Structure Grasshopper definitions to eliminate exponential data branch matching ({A;B;C}), using Flatten, Graft, Simplify, and Path Mapper.
4. Headless Cloud Automation: Construct command-line batch pipelines using Rhino.exe -runscript and REST payloads for compute.rhino3d servers.

Production Python Automation: Batch Solid Boolean & STEP Exporter

Save this script and execute inside Rhino Python 3 editor or via -runscript to automate solid unioning, manifold edge checks, and STEP export:

"""
Rhino 8 Automation: Batch Solid Union & Manifold STEP Exporter
Compatible with Rhino 8 CPython 3 and IronPython runtimes.
"""

import os
import rhinoscriptsyntax as rs
import scriptcontext as sc
import Rhino

def process_and_export_solids(output_step_path: str):
    # 1. Select all Polysurfaces / Breps in Document
    brep_ids = rs.ObjectsByType(rs.filter.polysurface | rs.filter.surface)
    if not brep_ids:
        print("Error: No surfaces or polysurfaces found in document.")
        return

    print(f"Found {len(brep_ids)} Brep objects. Validating solid status...")
    
    # 2. Check for Non-Manifold / Naked Edges
    solid_ids = []
    for obj_id in brep_ids:
        if rs.IsPolysurfaceClosed(obj_id):
            solid_ids.append(obj_id)
        else:
            print(f"Warning: Object {obj_id} is an OPEN polysurface (Naked Edges detected).")

    if not solid_ids:
        print("No valid closed solids to process.")
        return

    # 3. Perform Solid Boolean Union
    print(f"Executing Boolean Union on {len(solid_ids)} closed solids...")
    union_result = rs.BooleanUnion(solid_ids, delete_input=False)
    
    export_target_ids = union_result if union_result else solid_ids

    # 4. Export Selected Geometry to STEP
    os.makedirs(os.path.dirname(os.path.abspath(output_step_path)), exist_ok=True)
    rs.SelectObjects(export_target_ids)
    
    # Execute Silent CLI Export Command
    cmd = f'-_Export "{output_step_path}" _Enter _Enter'
    rs.Command(cmd, echo=False)
    
    print(f"Successfully exported geometry to STEP: {output_step_path}")

if __name__ == "__main__":
    process_and_export_solids("C:/Export/Assembled_Model.step")

Technical Troubleshooting Matrix

Command Line Syntax & Rhino.Compute Integration

# Windows CLI: Headless Rhino Script Execution
"C:\Program Files\Rhino 8\System\Rhino.exe" /nosplash /runscript="-_RunPythonScript C:\Pipeline\auto_process.py"

# Launch Rhino.Compute Headless Web Server
"C:\Program Files\Rhino 8\System\compute.geometry.exe" --port 8081

# Clean Corrupted Scheme Settings via PowerShell
Remove-Item -Path "$env:APPDATA\McNeel\Rhinoceros\8.0\settings\settings-Scheme__Default.xml" -Force

Essential File Locations

• Windows User Settings: %APPDATA%\McNeel\Rhinoceros\8.0\settings
• Windows Grasshopper Libraries: %APPDATA%\Grasshopper\Libraries
• macOS User Settings: ~/Library/Application Support/McNeel/Rhinoceros/8.0/
• macOS Grasshopper Libraries: ~/Library/Application Support/McNeel/Rhinoceros/MacPlugins/Grasshopper/Libraries

Agent Operational Directive

MANDATORY: Before running Boolean operations in Rhino, verify that objects are closed solids using rs.IsPolysurfaceClosed(). In Grasshopper workflows, normalize data tree branch depths to prevent combinatorial memory spikes.