From iPad sketch to DXF

A DXF is how a 2D drawing gets into Fusion, Onshape, Shapr3D or a laser cutter. It stores numbers, not pixels, so a sketch only comes through usable if it was drawn at true size, with clean outlines and the right units. Here’s how to get it right the first time.

1. Draw at true size

A DXF line from 0 to 150 is 150 units long, and the program that opens it decides what a unit is. So draw the part at its real size, in real units, rather than to a scale you’ll multiply out later. If the sketch was made to a scale, set that scale before you export, so 150 on the drawing is 150 in the file.

2. Close the outlines

CAD and laser software treat a closed outline as a profile: something to extrude, pocket or cut out. An outline with a gap, an overlapping end or a doubled line is just loose lines.

Corners meet exactly. Ends that nearly touch become a gap that stops a profile from closing.
No overhangs. Trim construction lines back to where they cross the outline.
No doubles. Two lines on top of each other cut twice on a laser and confuse a CAD import.

Drawn at true size, a 150 × 80 mm plate opens as 150 × 80 mm. Each kind of line on its own layer lets the next program treat it differently.

3. Pick the units, and say so

Choose millimetres or inches before you start, and keep them. DXF has a header setting for units, which most programs read. Some still ask when you open the file. Pick the same units you drew in, and turn off any option that scales the drawing to fit. A 16-inch part that opens as 16 millimetres is almost always a units mismatch.

4. Use layers for what each line is for

Put outlines, holes, construction lines, dimensions and notes on separate layers. In CAD you can import only the profile layers. A laser cutter often maps colour or layer to an operation, such as cut, score or engrave, so a layer per operation saves setup at the machine. Leave construction lines out of the export entirely, or hide their layer.

5. Open it, then check one length

In Fusion, insert the DXF onto a sketch plane. In Onshape, insert it into a sketch. Shapr3D and most laser software open DXF directly. Then measure one length you know, such as the overall width. If it matches, everything else will. If it’s off by 25.4, it’s a units mix-up. If it’s off by some other factor, the drawing wasn’t at true size.

DXF, SVG or PDF?

DXF for CAD and most laser and CNC software. Keeps layers.
SVG for Inkscape, Illustrator, Cricut-style cutters and many laser programs. Sized in millimetres or inches.
PDF to print at a true scale, for a template you cut around or a drawing for the shop.

Sketch to DXF in PencilCAD

In Settings → Tools, choose CAD. Tap Measure, then tap it again to pick millimetres or inches.
Draw with Line and Shape. Ends weld onto corners, so outlines close on their own.
Size it: drag dimensions with Measure, or write a size beside a line in Constrain and the line takes it.
Use Modify to trim overhangs, and Layers to keep construction lines on a layer you can hide.
Open More, share the page as DXF (R2000, with layers and colours) or SVG, and send it to your CAD app or cutter.