Fusion 360 CAM 3D Milling Operations

Create 3D surface machining operations via tools/fusion-cam-3d. All dimensions are mm. Output is JSON.

Orient yourself first

Before creating 3D operations, verify setup and available tools:

tools/fusion-cam-setup list                  # check for setups
tools/fusion-cam-setup operations            # existing operations
tools/fusion-cam-setup tools --type ball_end # check for ball end mills

If no setup exists, create one first with tools/fusion-cam-setup create.

When to use 3D vs 2D

Use 2D operations when...	Use 3D operations when...
Part is flat / prismatic	Part has curved surfaces
Vertical walls, flat floors	Sculpted / organic shapes
Pockets with flat bottoms	Mold cavities, dies
Simple profile cuts	Surface finishing quality matters
Drilling holes	Rest machining (remaining stock)

Operations at a glance

Roughing (material removal)

Operation	Best for
adaptive	Heavy roughing — constant engagement, fastest
pocket	Roughing with parallel passes

Finishing (surface quality)

Operation	Best for
parallel	General finishing — raster pattern
scallop [Extension]	Constant scallop height — best surface quality
pencil [Extension]	Inside corners and fillets
contour [Extension]	Waterline / Z-level — steep walls
steep-shallow [Extension]	Combined strategy — auto picks steep vs. shallow
horizontal	Flat areas only
radial	Round parts — passes radiate from center
spiral	Round parts — continuous spiral
morphed-spiral [Extension]	Freeform surfaces with guided spirals
flow [Extension]	UV-aligned finishing (guided by surface flow)

License requirements

Operations marked [Extension] require the Fusion 360 Manufacturing Extension. If your license doesn't include it, the handler returns a clear error message suggesting alternatives. Stick to: adaptive, pocket, parallel, horizontal, radial, spiral on a basic license.

3D Roughing

3D Adaptive Clearing

The best roughing strategy — maintains constant tool engagement for maximum material removal with minimum tool stress. Always start here for 3D parts.

# Basic 3D adaptive
tools/fusion-cam-3d adaptive --name "Rough" --stepdown 3 --stock-to-leave 0.5

# With optimal load control
tools/fusion-cam-3d adaptive --name "Heavy Rough" --stepdown 4 --optimal-load 3

# Leave stock for finishing
tools/fusion-cam-3d adaptive --name "Rough" --stepdown 3 --stock-to-leave 0.5 --axial-stock 0.2

# Bi-directional for faster clearing
tools/fusion-cam-3d adaptive --name "Fast Rough" --optimal-load 3 --both-ways

# With flat area detection
tools/fusion-cam-3d adaptive --name "Rough" --stepdown 3 --flat-area-detection

3D Pocket Clearing

Traditional roughing with parallel passes at each Z-level.

tools/fusion-cam-3d pocket --name "Pocket Rough" --stepdown 2 --stock-to-leave 0.5
tools/fusion-cam-3d pocket --name "Pocket Rough" --stepdown 2 --direction climb

3D Finishing

Parallel (raster)

General-purpose finishing. Passes are parallel lines across the model. Good starting point for most finishes.

# Basic parallel finish
tools/fusion-cam-3d parallel --name "Finish" --stepover 0.5

# At 45° angle
tools/fusion-cam-3d parallel --name "Finish 45" --stepover 0.3 --pass-angle 45

# Zero stock to leave (final pass)
tools/fusion-cam-3d parallel --name "Final" --stepover 0.3 --stock-to-leave 0

# Both directions
tools/fusion-cam-3d parallel --name "Cross Finish" --stepover 0.5 --direction both

Scallop

Constant scallop height — produces the most uniform surface quality. Passes follow the surface contours. Best for organic shapes.

tools/fusion-cam-3d scallop --name "Scallop Finish" --scallop-height 0.1
tools/fusion-cam-3d scallop --name "Fine Scallop" --scallop-height 0.05 --tolerance 0.005

Pencil

Cleans inside corners and fillets that larger tools can't reach. Run after parallel/scallop to clean up remaining material in tight areas.

tools/fusion-cam-3d pencil --name "Corners" --tool-number 5
tools/fusion-cam-3d pencil --name "Fillets" --stock-to-leave 0

3D Contour (waterline / Z-level)

Cuts at constant Z-heights. Excellent for steep walls where parallel leaves poor finish.

tools/fusion-cam-3d contour --name "Walls" --stepdown 0.5
tools/fusion-cam-3d contour --name "Fine Walls" --stepdown 0.2 --stock-to-leave 0

Steep & Shallow

Automatically combines waterline (steep areas) and raster (shallow areas) into one operation. Best all-around strategy when you don't know the geometry well.

# Default threshold (45°)
tools/fusion-cam-3d steep-shallow --name "Combined" --stepover 0.5

# Custom threshold angle
tools/fusion-cam-3d steep-shallow --name "Combined" \
  --threshold-angle 40 --steep-stepdown 0.3 --shallow-stepover 0.5

Horizontal

Finishes only flat/horizontal areas. Use after contour or parallel to clean up flats.

tools/fusion-cam-3d horizontal --name "Flats"

Radial

Passes radiate from a center point. Good for round parts, bowls, domes.

tools/fusion-cam-3d radial --name "Radial Finish" --center 0,0 --stepover 0.5

Spiral

Continuous spiral from outside in (or inside out). Good for round parts — no retract moves.

tools/fusion-cam-3d spiral --name "Spiral Finish" --stepover 0.5

Morphed Spiral

Like spiral but guided by the surface shape. Good for freeform surfaces with complex boundaries.

tools/fusion-cam-3d morphed-spiral --name "Morphed" --stepover 0.3

Flow

Follows the UV curves of the surface. Best when the surface has strong directional flow (like an airfoil or boat hull).

tools/fusion-cam-3d flow --name "Flow Finish" --stepover 0.3

Common parameters (all 3D operations)

--setup "Setup Name"         # target setup (defaults to last)
--name "Operation Name"      # display name
--stock-to-leave 0.5         # radial stock to leave (mm)
--axial-stock 0.2            # axial stock to leave (mm)
--stepover 0.5               # lateral step between passes (mm)
--stepdown 3                 # vertical step between levels (mm)
--tolerance 0.01             # surface tolerance (mm)
--boundary silhouette        # auto-detect machining boundary
--tool-number 3              # select tool from library
--tool-type "ball end mill"  # find tool by type
--rest-machining             # only cut remaining stock
--clearance-height 30        # clearance from stock top (mm)
--retract-height 10          # retract from stock top (mm)
--top-height 0               # top height offset (mm)
--bottom-height 20           # bottom height (mm)
--top-from stock top         # top height reference: 'stock top', 'model top' (default: 'stock top')
--bottom-from stock bottom   # bottom height reference: 'stock bottom', 'model bottom' (default: 'stock bottom')

Operation management

# Read current values of specific parameters
tools/fusion-cam-3d read-params --operation "Parallel" --params stockToLeave stepover topHeight_mode

# Duplicate an operation with all settings (tool, params, boundary)
tools/fusion-cam-3d duplicate --operation "Adaptive1" --new-name "Finish Pass"

# Edit an existing operation
tools/fusion-cam-3d edit --operation "Parallel" --stepover 0.3 --stock-to-leave 0

# Edit raw parameters
tools/fusion-cam-3d edit --operation "Adaptive" --params optimalLoad="2.5 mm"

# Rename
tools/fusion-cam-3d edit --operation "Parallel" --new-name "Final Finish"

# Suppress / unsuppress
tools/fusion-cam-3d suppress --operation "Scallop"
tools/fusion-cam-3d unsuppress --operation "Scallop"

# Delete
tools/fusion-cam-3d delete --operation "Old Rough"

Decision guide

I want to...	Command
Rough a 3D part	adaptive --stepdown 3 --stock-to-leave 0.5
General finish	parallel --stepover 0.5
Best surface quality	scallop --scallop-height 0.1
Clean inside corners	pencil
Finish steep walls	contour --stepdown 0.5
Auto-pick strategy	steep-shallow --stepover 0.5
Finish flat areas	horizontal
Finish a dome/bowl	spiral --stepover 0.5 or radial --center x,y
Follow surface flow	flow --stepover 0.3
Only cut remaining	parallel --rest-machining --stock-to-leave 0
Edit existing op	edit --operation O --stepover S
Skip an operation	suppress --operation O

Common patterns

Duplicate-and-edit pattern (fastest, most reliable)

Instead of creating operations from scratch, duplicate an existing one that's close to what you want:

tools/fusion-cam-3d duplicate --operation "Adaptive1" --new-name "Finish Pass"
tools/fusion-cam-3d edit --operation "Finish Pass" --stock-to-leave 0 --stepover 0.5

This preserves tool, boundary selection, and heights from the source operation.

Rough → semi-finish → finish

# 1. Heavy roughing with 3D adaptive (leave 0.5mm)
tools/fusion-cam-3d adaptive --name "Rough" --stepdown 3 --stock-to-leave 0.5 --tool-number 1

# 2. Semi-finish parallel (leave 0.1mm)
tools/fusion-cam-3d parallel --name "Semi-Finish" --stepover 1.0 --stock-to-leave 0.1 --tool-number 2

# 3. Final scallop finish (zero stock)
tools/fusion-cam-3d scallop --name "Finish" --scallop-height 0.05 --stock-to-leave 0 --tool-number 3

# 4. Clean corners
tools/fusion-cam-3d pencil --name "Corners" --stock-to-leave 0 --tool-number 3

Steep & shallow single-pass

tools/fusion-cam-3d adaptive --name "Rough" --stepdown 3 --stock-to-leave 0.3
tools/fusion-cam-3d steep-shallow --name "Finish" --stepover 0.3 --stock-to-leave 0

Rest machining (smaller tool cleans up)

# Large tool roughing
tools/fusion-cam-3d adaptive --name "Rough 12mm" --stepdown 3 --stock-to-leave 0.5 --tool-number 1

# Smaller tool cleans remaining stock
tools/fusion-cam-3d adaptive --name "Rest Rough 6mm" --stepdown 2 --stock-to-leave 0.5 --tool-number 2 --rest-machining

Key parameter names

What you want	Fusion parameter name	Example expression
Stock to leave	stockToLeave	0.5 mm
Top height mode	topHeight_mode	'from stock top'
Top height offset	topHeight_offset	-0.5 mm
Bottom height mode	bottomHeight_mode	'from stock bottom'
Bottom height offset	bottomHeight_offset	0 mm
Rest machining	useRestMachining	true
Rest source	restMaterialSource	'previousOperations'
Boundary mode	boundaryMode	'selection' or 'silhouette'
Pass angle	passAngle	45 deg
Tolerance	tolerance	0.01 mm

Common mistakes

• Setting height offset without mode — always set --top-from/--bottom-from with --top-height/--bottom-height or use read-params first to check current mode
• Using Extension-only operations without the license — check your Fusion license tier first, stick to parallel/adaptive/pocket on basic
• Using parallel on steep walls — parallel leaves a poor finish on walls >~60°. Use contour or steep-shallow instead
• Forgetting rest machining — when switching to a smaller tool, enable --rest-machining to avoid re-cutting already-machined areas
• Too large stepover — for ball end mills, stepover should be much less than tool diameter (typically 10-30% of diameter for finishing)
• No roughing before finishing — finishing operations assume most material is already removed. Always rough first
• Wrong tool type — 3D finishing usually needs ball end mills (spherical tip). Flat end mills leave stair-stepping on curved surfaces
• Stock to leave mismatch — roughing should leave >= what the finishing pass expects. If rough leaves 0.5mm, finish should use stock_to_leave=0