Updating from a new DXF

When the drawing changes, File > Update drawing from DXF…, or chipload update part.chipload --from part.dxf, takes in the new version and keeps the operations.

• Same shape, same id: shapes are matched by their DXF handle, the DXF’s own id for each entity, which CAD programs keep when you edit. An operation that selected a shape keeps it.
• Placed as before: the new drawing gets the same move, turn and scale.
• Drawn shapes stay: shapes drawn in Chipload are kept, with their ids.
• Several DXFs: --dxf ID says which one the new file replaces; the others stay as they are (Several drawings).
• The report lists what’s unchanged, changed, added and removed, and what that means for each operation:
  • geometry changed; check its toolpath;
  • layer X now uses the updated drawing;
  • shapes … no longer exist; choose its geometry again: the operation can’t run until you give it geometry again. The command line exits with 1 in that case.
• Units: taken from the last import. --units overrides them, if the new DXF is different.
• Stock: the stock isn’t changed. If the drawing now reaches past it, the report says so.

An empty project (File > New project, chipload new) takes its first DXF the same way: File > Import DXF into project….

A DXF saved by a program that gives every entity a new handle on each save makes every shape look new. Operations that select by layer survive that; ones that select single shapes need their geometry chosen again.