next3d 0.1.0

AI-native 3D CAD engine — 99 tools for creating, analyzing, and exporting parametric geometry via MCP

next3d — AI-Native 3D CAD Engine

A semantic 3D geometry system that lets AI agents create, modify, analyze, and export parametric 3D parts and assemblies through structured tool calls.

62 tools covering modeling, assembly, analysis, and export — usable from Claude Code, Claude Desktop, or any MCP client.

Quick Start with Claude Code

1. Install

# Clone and install
git clone https://github.com/buvi-org/next3d.git
cd next3d
pip install -e .

Requires Python 3.10+ and CadQuery (installed automatically).

2. Connect via MCP

Claude Code (CLI):

claude mcp add next3d -- next3d serve

Claude Desktop:

Add to your claude_desktop_config.json:

{
  "mcpServers": {
    "next3d": {
      "command": "next3d",
      "args": ["serve"]
    }
  }
}

3. Start Designing

Once connected, just ask Claude:

"Create a 100x60x20mm aluminum bracket with 4 mounting holes and export it as STEP and STL"

"Design a shaft with bearing seats at both ends, 200mm long, 15mm diameter"

"Build a stiffened chamber wall panel — 1 foot square, 3mm sheet with 50x50x3 RHS grid — and check if it can handle 0.1 MPa with less than 2mm deflection"

"Create an electronics enclosure 80x60x40mm, shell it to 2mm walls, add mounting holes, check it against FDM 3D printing design rules, then export STL"

---

What Claude Can Do

Create Geometry (9 tools)

create_box, create_cylinder, create_sphere, create_extrusion,
create_revolve, create_sweep, create_loft, create_sketch → sketch_extrude/sketch_revolve

Modify Parts (10 tools)

add_hole, add_counterbore_hole, add_pocket, add_circular_pocket,
add_boss, add_slot, add_fillet, add_chamfer, add_shell, add_draft

2D Sketches (8 tools)

create_sketch, sketch_add_line, sketch_add_arc, sketch_add_circle,
sketch_add_rect, sketch_add_constraint, sketch_extrude, sketch_revolve

Multi-Body Assembly (10 tools)

create_named_body, set_active_body, list_bodies, delete_body,
place_body, add_mate_constraint, check_interference,
add_standard_part, export_assembly, get_bom

Standard parts library: ISO metric fasteners M3–M12 (hex bolts, nuts, washers, socket head cap screws).

Query & Understand (5 tools)

get_summary, get_features, find_faces, query_geometry, measure_distance

Design Intelligence (7 tools)

check_design_rules, set_parameter, get_parameters,
add_datum, add_tolerance, get_gdt, suggest_gdt

Design rules for 6 processes: CNC milling, injection molding, FDM, SLA, sheet metal, casting. GD&T per ASME Y14.5 with auto-suggest.

Structural Analysis (5 tools)

run_fea, run_fea_parametric,
add_load, add_boundary_condition, run_topology_optimization

Real FEA solver: plate bending + beam stiffeners, 6 materials, 11 RHS sizes, parametric studies.

Export (7 tools)

export_step, export_stl, export_3mf, export_assembly,
export_script, render_png, undo

---

Example Workflows

Mounting Bracket

create_box(length=120, width=80, height=12)
add_hole(center_x=45, center_y=30, diameter=8)
add_hole(center_x=-45, center_y=30, diameter=8)
add_hole(center_x=45, center_y=-30, diameter=8)
add_hole(center_x=-45, center_y=-30, diameter=8)
add_fillet(radius=3, edge_selector="|Z")
check_design_rules(process="cnc_milling")
export_step(output_path="/tmp/bracket.step")

Shelled Electronics Housing (3D Print Ready)

create_box(length=80, width=60, height=40)
add_shell(thickness=2.0, face_selector=">Z")
add_hole(center_x=25, center_y=20, diameter=4, face_selector="<Z")
add_hole(center_x=-25, center_y=-20, diameter=4, face_selector="<Z")
add_fillet(radius=3, edge_selector="|Z")
check_design_rules(process="fdm_3d_print")
export_stl(output_path="/tmp/housing.stl")

Multi-Part Assembly with Fasteners

create_named_body(name="base_plate", shape_type="box", material="aluminum",
                  length=100, width=80, height=5)
set_active_body(name="base_plate")
add_hole(center_x=30, center_y=25, diameter=6.4)
add_hole(center_x=-30, center_y=25, diameter=6.4)

add_standard_part(name="bolt_1", part_type="hex_bolt", size="M6", length=20)
add_standard_part(name="bolt_2", part_type="hex_bolt", size="M6", length=20)
place_body(name="bolt_1", x=30, y=25, z=5)
place_body(name="bolt_2", x=-30, y=25, z=5)

get_bom()
export_assembly(output_path="/tmp/assembly.step")

Structural FEA — Stiffened Panel

run_fea(
  plate_width=304.8, plate_height=304.8,
  plate_thickness=3.0,
  grid_spacing_x=152.4, grid_spacing_y=152.4,
  rhs_size="50x50x3",
  material="steel_mild",
  pressure_mpa=0.1,
  bc_type="fixed_edges",
  weld_type="full"
)
→ max_deflection, stress, safety_factor, pass/fail verdict

Compare configurations:

run_fea_parametric(
  base_config={plate_width: 300, plate_height: 300, plate_thickness: 3,
               pressure_mpa: 0.05, grid_spacing_x: 150, grid_spacing_y: 150,
               rhs_size: "25x25x2"},
  variations=[
    {rhs_size: "25x25x2", label: "Small RHS"},
    {rhs_size: "50x50x3", label: "Large RHS"},
    {weld_type: "spot", label: "Spot welds"},
  ]
)

Revolved Shaft

create_revolve(
  points=[[5,0], [10,0], [10,15], [8,15], [8,40], [6,40], [6,50], [5,50]],
  angle_degrees=360
)
suggest_gdt()
export_step(output_path="/tmp/shaft.step")

---

CLI Usage

# Inspect a STEP file
next3d inspect part.step

# Export semantic graph as JSON
next3d graph part.step --format json

# List recognized features
next3d features part.step

# Run a modeling pipeline
next3d build '[{"tool":"create_box","params":{"length":100,"width":60,"height":20}},
               {"tool":"add_hole","params":{"center_x":0,"center_y":0,"diameter":10}}]' \
  -o output.step

# Start the MCP server
next3d serve

---

Architecture

AI Agent (Claude, GPT, etc.)
    ↓ tool calls
MCP Server (next3d serve)
    ↓
Tool Executor → validates params, dispatches
    ↓
Modeling Session → stateful, multi-body, undo
    ↓
Kernel (CadQuery / OpenCascade) → exact B-Rep geometry
    ↓
Semantic Graph → topology, features, relationships
    ↓
Export (STEP, STL, 3MF, PNG, CadQuery script)

Tech Stack

Layer	Technology
CAD Kernel	OpenCascade via CadQuery
Graph	NetworkX
Data Models	Pydantic v2
FEA Solver	NumPy + SciPy sparse
CLI	Click + Rich
AI Protocol	MCP (Model Context Protocol)

---

Development

pip install -e ".[dev]"
pytest                     # run all tests (288)
pytest -k "FEA"           # run FEA tests only
pytest -k "TestSketch"    # run sketch tests only

License

MIT