pcb-rnd user manual

# pcb-rnd - user manual

## 7.1 IO plugins

### 7.1.2 io_pcb

Historically geda/PCB is the predecessor of pcb-rnd, but pcb-rnd has switched native file format during the big data model rewrite (2016..2017). This means the old geda/PCB file formats (board and element) are supported only as alien file formats, with the usual alien format limitations.

At the moment pcb-rnd supports loading files up to geda/PCB version 4.3 (file version 20180318). This includes loading the latest additions of blind/buried vias, center-specified pads and mask value in routing style. When saving in this format, pcb-rnd will pick a much older format version, see limitations below.

Extras in pcb-rnd:

- minor bugfixes so that numeric roundings on corner cases are better
- unlike geda/PCB, pcb-rnd won't crash on invalid bbvia span values but throw an error message with the coords and load the via as thru-hole
- pcb-rnd can save with different units
- pcb-rnd makes an effort to preserve the unit style so a load-save operation causes less changes to the file than in geda/PCB
- pcb-rnd has better support for ancient (pre-2000) file versions

Limitations in pcb-rnd:

- saving files: the newest geda/PCB file format version pcb-rnd can save is, 20100606; that already has polygon holes but:
  - no center-defined pads so pad format is converted to line-based (in fact geda/PCB 4.3 also does this conversion on save)
  - no blind/buried vias
  - no mask value in routing style