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Lothal

Importing frame outlines

The frame designer’s Import button brings in an outline you drew elsewhere, in Inkscape, Illustrator or a CAD program, or a DXF from a cutting service. It arrives as plates you can edit, weigh and cut again. Once imported, every number in the designer is about the part you intend to cut.

What is read

Section titled “What is read”
  • Closed shapes become plates. A shape inside another shape becomes a hole in it. A shape inside a hole is its own plate again.
  • Curves are flattened into short straight segments, finer than a cutter’s line.
  • Tiny closed loops (smaller than about half a millimetre square) are ignored as stray clicks.
  • The imported shapes are centred on the drawing, whatever position they had in the file.

Units

Section titled “Units”

Getting the scale wrong would look normal on screen and come out of the cutter the wrong size, so the scale is worked out from the file, not assumed:

  • SVG with a real width and height (in mm, cm or in) and a viewBox: scaled to millimetres exactly. This is what Lothal’s own SVG export writes.
  • SVG in pixels, or with no units: read at 96 pixels per inch, and the designer says so, with the resulting span in millimetres. Check that span against what you drew.
  • DXF has no units by convention: numbers are read as millimetres, as cutting services expect.

There is no Y flip

Section titled “There is no Y flip”

SVG’s Y runs down the page, and so does the designer’s plan (a frame is drawn nose-up). The two already agree, so a shape arrives the way round it was drawn, and Lothal’s own SVG exports import back unchanged.

What is not read

Section titled “What is not read”
  • SVG text, strokes, styles and fills. A cut file is geometry; a label is not a part.
  • DXF splines. A DXF containing a SPLINE is refused, with a message, rather than imported with edges missing. Re-export it with splines converted to polylines; most CAD programs have one setting for that.
  • Arm centrelines. An imported shape is never treated as an arm, because a file does not say which end of a shape bolts to the middle of the drone.

The hole limit

Section titled “The hole limit”

Neither SVG nor DXF records which outline owns which hole. Lothal works it out from what sits inside what. So a hole that crosses its plate’s edge cannot come back as a hole; it is imported as its own outline. Keep every hole fully inside its plate.

If a file cannot be read, nothing is changed in the drawing.

Section titled “Related”

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