Tutorial: Simple Box

Tutorial: Simple Box

Level: Beginner | Time: 5 minutes | Tools used: create_primitive, measure, fillet_edges, export_model

Goal

Create a 50x30x20 mm box with 2 mm fillets on all edges, then export to STL. This tutorial introduces the core Act-mode workflow: you describe what you want, and the AI calls the right tools.

What You Will Build

A rounded rectangular box suitable for 3D printing. Final dimensions approximately 50x30x20 mm with all sharp edges replaced by 2 mm radius fillets.

Steps

Step 1: Set Up Your Environment

1. Launch FreeCAD and switch to the FreeCAD AI workbench (dropdown in the toolbar, or View > Workbench > FreeCAD AI).
2. Open the AI chat panel if it is not visible: View > Panels > FreeCAD AI.
3. Open settings (gear icon in the chat panel) and confirm:
   • Mode is set to Act
   • A working LLM provider is selected
4. Create a new empty document: File > New.

You should see an empty 3D viewport and an empty model tree on the left.

Step 2: Create the Box

Type the following in the chat panel and press Enter:

Create a box 50mm long, 30mm wide, 20mm high

What the AI does:

The AI calls the create_primitive tool:

create_primitive(
    shape_type="box",
    length=50,
    width=30,
    height=20
)

What you should see:

• A rectangular box appears in the 3D viewport
• The model tree shows a Body with a Pad feature
• The chat panel shows the tool call and its result with the object name

Verify: Rotate the viewport (middle-mouse-drag) to confirm the box looks correct. It should sit on the XY plane with one corner at the origin.

Step 3: Apply Fillets

Type:

Apply 2mm fillets to all edges

What the AI does:

1. Calls measure with measure_type="edges" to discover all edge names on the box
2. Calls fillet_edges with the full edge list and radius=2

measure(
    object_name="Pad",
    measure_type="edges"
)

fillet_edges(
    object_name="Pad",
    edge_names=["Edge1", "Edge2", ..., "Edge12"],
    radius=2
)

What you should see:

• All 12 edges of the box become rounded
• The model tree shows a Fillet feature under the Body
• The box now looks like a smooth, rounded brick

Troubleshooting: If the AI fillets only some edges, type "fillet the remaining edges too" and it will pick up the ones it missed.

Step 4: Export to STL

Type:

Export to STL at /tmp/my-box.stl

What the AI does:

export_model(
    format="stl",
    filename="/tmp/my-box.stl"
)

What you should see:

• The chat confirms the export succeeded
• The file /tmp/my-box.stl now exists and can be opened in a slicer (Cura, PrusaSlicer, etc.)

Verify: Check the file size. A box with fillets typically produces an STL of 50-200 KB depending on tessellation.

Step 5 (Optional): Export to STEP

If you want a CAD-native format instead:

Also export as STEP to /tmp/my-box.step

STEP files preserve exact geometry (no triangulation) and are better for sharing with other CAD software.

What You Learned

Concept	Details
Act mode	You type natural language; the AI selects and calls tools automatically
Primitives	create_primitive creates boxes, cylinders, spheres, and cones
Edge measurement	measure with measure_type="edges" lists all edges on an object
Fillets	fillet_edges rounds edges by a given radius
Export	export_model writes STL, STEP, or IGES files

Next Steps

• Try changing the dimensions or fillet radius
• Create a cylinder and apply chamfers instead of fillets
• Move on to Tutorial: Enclosure for a multi-step build