fusion-construction - SKILL.md Agent Skill

name: fusion-construction description: Create and manage construction geometry in Fusion 360 — planes, axes, points, and measurements. Use when the user asks to create reference geometry, offset planes, angled planes, midplanes, construction axes, construction points, measure distances, measure angles, or query body properties.

Fusion 360 Construction / Reference Geometry

Control Fusion 360 construction geometry via tools/fusion-construction. All dimensions are mm. Output is JSON.

Orient yourself first

tools/fusion-construction planes     # all construction planes
tools/fusion-construction axes       # all construction axes
tools/fusion-construction points     # all construction points
tools/fusion-construction measure --body Body1   # body properties (volume, area, CoM)
tools/fusion-construction vertices --body Body1  # all vertex positions

Construction Planes

Planes are the foundation for sketches. Fusion provides 3 built-in planes (XY, XZ, YZ) and you can create custom ones.

Create offset plane

The most common operation — place a plane parallel to a base plane at a distance:

# 50mm above XY plane
tools/fusion-construction offset-plane --base xy --offset 50 --name ShelfPlane

# 25mm in front of XZ plane
tools/fusion-construction offset-plane --base xz --offset 25

# Offset from an existing custom plane
tools/fusion-construction offset-plane --base ShelfPlane --offset 19.05 --name NextShelf

Create angled plane (arbitrary orientation)

Two input modes:

# Mode 1: Point + normal vector
tools/fusion-construction angled-plane --point 50,50,50 --normal 1,1,0 --name DiagonalCut

# Mode 2: Three points defining the plane
tools/fusion-construction angled-plane --p1 0,0,0 --p2 100,0,0 --p3 0,100,50 --name RampPlane

Plane rotated around a line

Create a tilted plane by rotating a base plane around a sketch line:

tools/fusion-construction plane-by-angle --base xy --sketch AxisSketch --line 0 --angle 45 --name TiltedPlane

Midplane

Create a plane halfway between two parallel planes or faces:

# Between two built-in planes
tools/fusion-construction midplane --p1 xy --p2 ShelfPlane --name MidShelf

# Between two faces of a body (use body:face syntax)
tools/fusion-construction midplane --p1 Panel1:Panel1_face_0 --p2 Panel1:Panel1_face_1

Tangent plane

Create a plane tangent to a curved surface:

tools/fusion-construction tangent-plane --body Cylinder1 --face Cylinder1_face_2 --name TangentCut

Delete a plane

tools/fusion-construction delete-plane --name MyOldPlane

Construction Axes

Axes are used for revolves, patterns, and as references.

# List all axes
tools/fusion-construction axes

# Through two points
tools/fusion-construction axis-2pt --p1 0,0,0 --p2 100,100,0 --name DiagonalAxis

# Along a body edge
tools/fusion-construction axis-edge --body Body1 --edge Body1_edge_0 --name EdgeAxis

# Perpendicular to a face (through its center)
tools/fusion-construction axis-perp --body Body1 --face Body1_face_0 --name FaceNormal

# At the intersection of two planes
tools/fusion-construction axis-intersect --p1 xy --p2 xz --name OriginX

# Delete
tools/fusion-construction delete-axis --name MyAxis

Construction Points

Reference points for snapping, dimensioning, and plane creation.

# List existing
tools/fusion-construction points

# At specific coordinates
tools/fusion-construction point --pos 50,30,20 --name CenterRef

# At a body vertex
tools/fusion-construction point-vertex --body Body1 --index 0 --name Corner

# At center of edge (midpoint) or face (centroid)
tools/fusion-construction point-center --body Body1 --entity Body1_edge_3 --name EdgeMid

# Delete
tools/fusion-construction delete-point --name CenterRef

Measurements

Distance between entities

The --e1 and --e2 flags use a type:value format:

Entity spec	Meaning
`body:BodyName`	Entire body
`face:Body:FaceID`	A specific face
`edge:Body:EdgeID`	A specific edge
`plane:xy`	A construction plane
`axis:z`	A construction axis
`point:x,y,z`	An arbitrary 3D point

# Distance between two bodies
tools/fusion-construction distance --e1 body:Panel1 --e2 body:Panel2

# Distance from a point to a plane
tools/fusion-construction distance --e1 point:50,30,20 --e2 plane:xy

# Distance between a face and a body
tools/fusion-construction distance --e1 face:Body1:Body1_face_0 --e2 body:Body2

# Distance between two points
tools/fusion-construction distance --e1 point:0,0,0 --e2 point:100,100,100

Angle between planes/faces

# Angle between two built-in planes
tools/fusion-construction angle --e1 plane:xy --e2 plane:xz

# Angle between a face and a plane
tools/fusion-construction angle --e1 face:Wedge:Wedge_face_0 --e2 plane:xy

# Angle between two faces
tools/fusion-construction angle --e1 face:Body1:Body1_face_0 --e2 face:Body1:Body1_face_2

Body physical properties

tools/fusion-construction measure --body Body1

Returns: volume, surface area, center of mass, bounding box, dimensions, face/edge/vertex counts.

Vertex listing

tools/fusion-construction vertices --body Body1

Returns all vertex positions — useful for polyhedron workflows and verifying geometry.

Complete command reference

Planes

Command	What it does
`planes`	List all planes (3 built-in + user-created)
`offset-plane --base P --offset D [--name N] [--component C]`	Plane parallel to base at distance
`angled-plane --point x,y,z --normal x,y,z [--name N]`	Plane at arbitrary orientation (point+normal)
`angled-plane --p1 x,y,z --p2 x,y,z --p3 x,y,z [--name N]`	Plane through three points
`plane-by-angle --base P --sketch S --line I --angle D [--name N]`	Plane rotated around sketch line
`midplane --p1 ID --p2 ID [--name N]`	Midplane between two planes/faces
`tangent-plane --body B --face F [--point x,y,z] [--name N]`	Plane tangent to curved surface
`delete-plane --name N`	Delete a construction plane

Axes

Command	What it does
`axes`	List all axes (3 built-in + user-created)
`axis-2pt --p1 x,y,z --p2 x,y,z [--name N]`	Axis through two points
`axis-edge --body B --edge E [--name N]`	Axis along a body edge
`axis-perp --body B --face F [--name N]`	Axis perpendicular to face
`axis-intersect --p1 PLANE --p2 PLANE [--name N]`	Axis at intersection of two planes
`delete-axis --name N`	Delete a construction axis

Points

Command	What it does
`points`	List all construction points
`point --pos x,y,z [--name N]`	Point at coordinates
`point-vertex --body B --index I [--name N]`	Point at body vertex
`point-center --body B --entity E [--name N]`	Point at center of edge/face
`delete-point --name N`	Delete a construction point

Measurements

Command	What it does
`distance --e1 SPEC --e2 SPEC`	Minimum distance between entities
`angle --e1 SPEC --e2 SPEC`	Angle between planes/faces
`measure --body B`	Body properties (volume, area, CoM, counts)
`vertices --body B`	All vertex positions of a body

Decision guide

I want to...	Command
Sketch at a specific height	`offset-plane` then sketch on it
Create a miter cut plane	`angled-plane` with the bisector normal
Find the middle of a panel	`midplane` between its two faces
Place a hole at a body's center	`measure` to get center of mass
Check if two panels are parallel	`angle` between their faces (0° = parallel)
Revolve around a diagonal	`axis-2pt` then use in fusion-solid revolve
Pattern along an edge	`axis-edge` then use for pattern direction
Verify body dimensions	`measure` for exact volume/area/bounds
Find exact corner positions	`vertices` to list all vertex coordinates

Common mistakes

Offset direction confusion. Positive offset goes in the plane's normal direction. For XY: +Z (up). For XZ: +Y (into model). For YZ: +X (right).
Forgetting to name planes. Auto-generated names like "Plane1" are hard to reference later. Always use --name.
Deleting helper geometry. Angled planes in parametric mode create helper sketches/planes. Deleting them breaks the construction plane.
Measuring with wrong entity type. The distance command needs explicit type:value format. body:Body1 not just Body1.