Turn a filled SVG into a layered, CNC-cuttable sign in FreeCAD.

Every filled shape in the SVG becomes a part cut from sheet material. Parts are stacked "outside in": whatever is painted on top of something else sits one layer higher. Each part gets a shallow pocket (inset) for the parts resting on it, so everything locates itself during glue-up.

You get two FreeCAD files, and each one again as STEP:

The STEP files contain the parts only: no layer groups and no sheet outline. They are large (tens of MB for a detailed logo) because every curve is a fine polyline; a coarser --tolerance shrinks them. Skip them with --no-step.

With --dxf you also get <name>_layout.dxf, the flat layout as 2D outlines. See Exports.

• FreeCAD 1.0 or newer
• Python 3.10 or newer with svgelements, shapely (2.0+) and ezdxf - uv takes care of all of that for you

Developed and tested on macOS. Nothing in it is macOS-specific, but Windows and Linux are untested.

Get the code:

git clone https://github.com/kjellski/svg2sign.git
cd svg2sign

Install uv; that is the whole setup. The script lists its own dependencies, and uv installs them - and a suitable Python if needed - the first time you run it:

./svg2sign.py --help

On Windows, or if the script is not executable:

uv run svg2sign.py --help

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt
python svg2sign.py --help

On Windows activate with .venv\Scripts\activate. Wherever this README says ./svg2sign.py, use python svg2sign.py instead.

FreeCAD is found automatically if FreeCAD / freecadcmd is on your PATH, or in /Applications/FreeCAD.app on macOS. Otherwise point to it with --freecad:

With --headless, point to freecadcmd (FreeCADCmd.exe on Windows) instead.

Interactive - it asks for everything, Enter accepts the default:

./svg2sign.py

SVG file: logo.svg
Overall width [mm] [1000.0]:
Overall height [mm] [1000.0]:
Material thickness [mm] [12.0]:
Inset (pocket) depth [mm], 0 = none [3.0]:
Inset play per side [mm] [0.2]:
Gap between parts on the sheet [mm] [10.0]:

Non-interactive - anything given as a flag is not asked; --yes takes defaults for the rest:

./svg2sign.py --svg logo.svg --width 1000 --height 1000 \
              --thickness 12 --inset 3 --play 0.2 --gap 10 --yes

A FreeCAD window opens with both documents once the build is done. A sign with around 80 parts takes about a minute.

STEP (default, --no-step to skip) - <name>_sign.step and <name>_layout.step. Solids with pockets, one body per part, named like the part, positioned as in the matching FreeCAD file. In Fusion 360: File > Open > Open from my computer. Colours are not carried over reliably.

DXF (--dxf) - <name>_layout.dxf, millimetres, closed polylines, all sheets side by side as in the layout file. One layer per kind of cut:

Pockets that run off the edge of a part are drawn 1 mm past that edge so the cutter clears it. The DXF is written directly and does not need FreeCAD.

• Fills only. Strokes are ignored. In Inkscape: Path > Stroke to Path.
• Text must be paths. In Inkscape: Path > Object to Path.
• Paint order is stacking order. Objects lower in the layer list are lower in the sign. A background shape that everything sits on becomes the backing plate.
• Holes show the layer below. A ring-shaped path is cut as a ring.
• Label your objects (Inkscape: Object Properties > Label). Labels become part names in FreeCAD; unlabelled paths inherit their group's label or use their id. Shapes sharing a label get _a, _b, ... appended.
• Colours are taken from the fill and only used for display.

Shapes are processed in paint order:

1. A shape that lies on nothing is layer 0.
2. Otherwise it goes one layer above the highest shape it overlaps. Overlaps smaller than --min-overlap of the shape's own area are ignored, so parts that merely touch their neighbours stay on the same layer.
3. Each layer sits thickness - inset above the one below.
4. A part is pocketed for every shape exactly one layer above it. The pocket is the upper shape's footprint grown by --play, cut --inset deep.
5. Every connected piece of a shape is its own part - each letter of a text, each dot.

For the layout, each part is turned to its smallest bounding box and packed by that box. Parts are only rotated in the sheet plane, never flipped.

• X and Y overlap by N mm2 on the same layer - two parts on one layer collide. Small values need a little sanding; large ones mean the SVG wants fixing.
• X would sink into Y - reduce the inset - a part spans more than one layer down and would collide. Keep the inset at or below half the thickness.
• more than one bottom-layer shape - there is no single backing plate.
• pocket failed on X, left without inset - FreeCAD could not cut that pocket; the part is still there, just flat on top.

• Outlines are fine polylines, not true curves or arcs.
• Packing uses bounding boxes. Small parts are not nested into the waste inside larger ones.
• There is no check against the cutter diameter. Pockets and holes narrower than the bit cannot be milled, and inside corners of pockets come out rounded while the matching part corners are sharp - round those by hand or use a smaller bit.
• No toolpaths or tabs. Use the FreeCAD CAM workbench on the layout file, or take the layout STEP or DXF into Fusion 360 or your CAM of choice.
• fill-rule is treated as even-odd.

• LICENSE - coffee-ware.
• requirements.txt - dependencies for pip users; mirrors the header in svg2sign.py.
• svg2sign.py - prompts, SVG parsing, stacking, pockets and packing.
• freecad_build.py - runs inside FreeCAD and builds the two documents. Started by svg2sign.py; not meant to be run by hand.

Coffee-ware: do whatever you want with it, keep the notice, and if we meet some day and you think it was worth it, buy me a coffee. No warranty.