vcad

name	vcad
description	Create 3D CAD models using vcad MCP tools. Use when the user asks to create 3D parts, mechanical components, enclosures, brackets, gears, or any parametric geometry. Supports primitives, sketch-based operations (extrude, revolve, sweep, loft), booleans, patterns, fillets, shell, assemblies, and export to STL/GLB.

vcad - Parametric CAD for AI Agents

Create 3D CAD models programmatically using the vcad MCP tools. All dimensions are in millimeters.

Available Tools

Tool	Purpose
create_cad_document	Build geometry from primitives, sketches, and operations
export_cad	Export to STL (3D printing) or GLB (visualization)
inspect_cad	Get volume, surface area, bounding box, center of mass, mass
import_step	Import geometry from STEP files
open_in_browser	Generate shareable vcad.io URL
get_changelog	Query recent changes and features

For assembly and physics tools, see the assembly-physics skill.

Output Format

Use "format": "vcode" (default) for token-efficient output (~5x smaller). Use "format": "json" for human-readable debugging.

Part Types

Each part must use exactly ONE base geometry type:

Primitive-based

{
  "name": "plate",
  "primitive": {"type": "cube", "size": {"x": 100, "y": 60, "z": 5}},
  "operations": [...]
}

Extrude-based (sketch → solid)

{
  "name": "bracket",
  "extrude": {
    "sketch": {
      "plane": "xy",
      "shape": {"type": "rectangle", "width": 40, "height": 20, "centered": true}
    },
    "height": 10
  }
}

Revolve-based (sketch → solid of revolution)

{
  "name": "vase",
  "revolve": {
    "sketch": {
      "plane": "xy",
      "shape": {
        "type": "polygon",
        "points": [
          {"x": 10, "y": 0}, {"x": 15, "y": 20},
          {"x": 12, "y": 40}, {"x": 14, "y" 
                 
        
      
    
     
     
  

Sweep-based (sketch along path)

{
  "name": "tube",
  "sweep": {
    "sketch": {
      "shape": {"type": "circle", "radius": 5}
    },
    "path": {"type": "line", "start": {"x": 0, "y": 0, "z": 0}, "end": {"x": 50, "y": 0, "z": 30}
  

Helix path for springs/threads:

"path": {"type": "helix", "radius": 20, "pitch": 10, "height": 60}

Optional sweep parameters: twist_deg, scale_start, scale_end.

Loft-based (interpolate between sketches)

{
  "name": "transition",
  "loft": {
    "sketches": [
      {"plane": "xy", "at": {"x": 0, "y": 0, "z": 0}, "shape": {"type": "rectangle", "width": 40, "height": 40, "centered": true}},
      {"plane": "xy", "at":           
    
  

Sketch Shapes

Sketches are used by extrude, revolve, sweep, and loft operations:

Shape	Parameters
rectangle	width, height, centered (bool, default false)
circle	radius
polygon	points (array of {x, y}), closed (default true)

Sketch planes: "xy" (default), "xz", "yz". Origin set with "at": {x, y, z}.

Primitive Origins

Primitive	Origin	Extent
Cube	Corner at (0,0,0)	Extends to (size.x, size.y, size.z)
Cylinder	Base center at (0,0,0)	Height along +Z
Sphere	Center at (0,0,0)	Radius in all directions
Cone	Base center at (0,0,0)	Height along +Z, radius_bottom/radius_top

Positioning

The at parameter for boolean operations and holes:

1. Absolute: {"x": 25, "y": 15, "z": 0} — exact coordinates in mm
2. Named: "center", "top-center", "bottom-center" — relative to base primitive
3. Percentage: {"x": "50%", "y": "50%"} — percentage of base primitive bounds

Operations

Applied in order after the base geometry:

Operation	Key Parameters
union	primitive, at
difference	primitive, at
intersection	primitive, at
hole	diameter, at, depth (omit for through-hole)
translate	offset: {x, y, z}
rotate	angles: {x, y, z} (degrees)
scale	factor: {x, y, z}
linear_pattern	direction: {x, y, z}, count, spacing
circular_pattern	axis_origin, axis_dir, count, angle_deg
fillet	radius — rounds all edges
chamfer	distance — bevels all edges
shell	thickness — hollows the part

Materials

Assign via "material" on each part: "steel" (density 7850), "aluminum" (2700), "default".

inspect_cad reports mass when density is available.

Common Patterns

Plate with Corner Holes

{
  "parts": [{
    "name": "mounting_plate",
    "primitive": {"type": "cube", "size": {"x": 100, "y": 60, "z": 5}},
    "operations": [
      {"type": "hole", "diameter": 4, "at": {"x": 10, "y": 10}},
      {"type":        
              
              
    
  

Cylinder with Blind Hole

{
  "parts": [{
    "name": "bushing",
    "primitive": {"type": "cylinder", "radius": 15, "height": 20},
    "operations": [
      {"type": "hole", "diameter": 10, "depth": 15, "at": "center"}
    ]
  }]
}

L-Bracket

{
  "parts": [{
    "name": "bracket",
    "primitive": {"type": "cube", "size": {"x": 40, "y": 40, "z": 5}},
    "operations": [
      {"type": "union", "primitive": {"type": "cube", "size": {"x": 5, "y": 40, "z":        
              
                     
    
  

Flange with Circular Bolt Pattern

{
  "parts": [{
    "name": "flange",
    "primitive": {"type": "cylinder", "radius": 40, "height": 10},
    "operations": [
      {"type": "hole", "diameter": 20, "at": "center"},
      {"type": "difference", "primitive": {"type": "cylinder", "radius": 4, "height":        
                         
    
  

Linear Pattern of Holes

{
  "parts": [{
    "name": "rail",
    "primitive": {"type": "cube", "size": {"x": 200, "y": 20, "z": 10}},
    "operations": [
      {"type": "difference", "primitive": {"type": "cylinder", "radius": 3, "height": 15}, "at": {"x"     
                  
    
  

Extruded T-Profile

{
  "parts": [{
    "name": "t_beam",
    "extrude": {
      "sketch": {
        "plane": "xz",
        "shape": {
          "type": "polygon",
          "points": [
            {"x": -25, "y": 0}, {"x": 25, "y": 0},
            {"x": 25, "y": 3}, {   
                   
                   
          
        
      
       
    
  

Shelled Box (Enclosure)

{
  "parts": [{
    "name": "enclosure",
    "primitive": {"type": "cube", "size": {"x": 80, "y": 60, "z": 40}},
    "operations": [
      {"type": "shell", "thickness": 2}
    ]
  }]
}

Filleted Part

{
  "parts": [{
    "name": "rounded_block",
    "primitive": {"type": "cube", "size": {"x": 30, "y": 20, "z": 15}},
    "operations": [
      {"type": "fillet", "radius": 2}
    ]
  }]
}

Spring (Helix Sweep)

{
  "parts": [{
    "name": "spring",
    "sweep": {
      "sketch": {"shape": {"type": "circle", "radius": 1.5}},
      "path": {"type": "helix", "radius": 10, "pitch": 8, "height": 40}
    },
    "material": "steel"
  }]
}

Workflow

1. Create — create_cad_document to build geometry
2. Inspect — inspect_cad to verify dimensions, volume, and mass
3. Export — export_cad to save as .stl or .glb
4. Share — open_in_browser to generate a vcad.io URL

Tips

• Holes default to through-holes; specify depth for blind holes
• Use percentage positioning for parametric designs that scale
• Cube origin is at corner — add half-size to center operations
• Cylinder/cone origins are at base center — no X/Y offset needed for centered holes
• Always extend cutting cylinders past the part (the hole operation does this automatically)
• fillet and chamfer apply to all edges — use them as the last operation
• shell hollows the entire part — combine with difference to remove specific faces
• For multi-part designs, define each part in the parts array with a unique name
• Use "format": "vcode" (default) to save tokens in the response