Flat-pack DXF to 3D assembly
Turn the DXF cutting sheets of a CNC flat-pack design into a 3D model that shows how every part fits together.
CNC furniture, such as the designs on Opendesk, often comes as cutting sheets: DXF files with every part laid flat on a sheet of plywood, ready for the CNC router. They show what to cut, but not how the parts go together. SchoolCAD can read the sheets, work out how the parts join, and build the whole thing in 3D.
Try it first with the sample Wiki Booth (Opendesk) in Documents → Sample designs. It was made this way from its two cutting sheets.
How to use it#
- Open the dialog. Any of these work:
- Search for Flat-pack DXF to assembly (click Search, or press `).
- Drag the DXF files onto the SchoolCAD window.
- Click Open file and choose the DXF files.
- If you have not already, click Choose DXF files… and pick every sheet of the design at once.
- Type a name for the design, then click Assemble.
- Wait while SchoolCAD works it out. A big design can take up to half a minute. The files are not uploaded: it all happens on your computer.
- Look at the Front and Side pictures. If it is not standing the right way up, click Upside down, Tip forward, On its side or Turn round until it is.
- Click Open as a new design.
What the files need#
SchoolCAD reads what to do from the layer names in the DXF. Most CNC furniture uses names like these:
| Layer name | What it means |
|---|---|
TOP-CUT-OUTSIDE_18MM | The outline of a part, cut right through an 18 mm sheet |
TOP-CUT-INSIDE_18MM | A hole or slot cut right through, inside a part |
TOP-POCKET-INSIDE_9MM | A pocket 9 mm deep, cut down from the top face |
TOP-HOLE-6MM-DIAM_14MM | A drilled hole, 6 mm across and 14 mm deep |
BOTTOM-… | The same, worked from the other face |
Layers starting with 00-NOPRINT (notes and borders) are left out. If a sheet is drawn more than once (front face, reverse face, both faces), SchoolCAD uses the first drawing of the parts.
How it works out the joints#
- Tabs and slots. A tab is a bit of a part's edge that sticks out. A slot is a pocket or hole the same length. SchoolCAD puts each tab into a slot that fits it, so the shoulder of the part sits against the face of the board.
- Notches. A tab that goes right through a board fits a notch cut into that board's edge.
- Dowels. Two parts with the same pattern of drilled holes are glued face to face, with dowels in the holes.
- Grooves. A part with no tabs, such as a shelf, can sit with its edge in a long groove. SchoolCAD slides it in as far as it will go.
It tries every way each part could fit, and keeps the one where the most joints fit and no parts pass through each other. Then it guesses which way up the furniture stands: on its legs, with its open side at the front.
What you get#
Every part is a normal SchoolCAD part, named by where it was cut, such as Sheet 2, part 4. Each one is drawn on the Top plane exactly where it sat on its sheet, extruded, and has its pockets and holes cut. Then a Place step (a Transform) moves it into the assembly. Drag the rollback bar in the feature tree up above the Place steps to see the parts back on their sheets.
You can now make Assembly instructions, a Cut list or a drawing, or change the design. Rename the parts so the instructions make sense (double-click a part in the Parts list).
If it does not work#
- This DXF has no flat-pack layers. The file has no outline layer with a name like
TOP-CUT-OUTSIDE_18MM. To use a drawing in a sketch instead, start a sketch and use Insert image. - Some parts could not be placed. They lie flat on the floor beside the model. Their joints did not match any others, often because a sheet is missing. Choose all the sheets together.
- Some parts pass through each other. Check the parts it names. A design with very loose or very tight slots may not match well.
- A part is the wrong way round. Parts held by only one tab (such as a sign on a roof) can fit two ways. SchoolCAD stands them on top of the board they fit into.