With "DXF : symboles en blocs" ticked in the export dialog, or
--dxf-blocks on the command line, each symbol definition a folio uses is
written once as a DXF block and every placed symbol as an INSERT of it.
A CAD program then selects, counts and replaces a symbol as one object.
The block is drawn by the same code as a symbol drawn in full, as if
the symbol sat unturned at the folio's origin, which is DXF (0,
sheetHeight): that is the block's base point, so the INSERT carries the
symbol's position and quarter-turn and nothing else. Blocks have to come
before any entity, so the export collects them first and dxfBegin()
writes them in its BLOCKS section. Entities in a block keep their own
layers. Off by default; with it off the file is unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>