Incorrect Gerber Import: Rotated Element / Beta 8.993

[F.Haskamp]

The current beta 8.993 has issues importing Gerber files with rotated elements.

How to reproduce:

1. In KiCad: Place a resistor footprint on the PCB, use Ctrl+M to rotate it 120 degrees, attach some tracks, plot as Gerber
2. Check in another Gerber viewer of your choice if everything is fine (e.g. https://gerber.ucamco.com/ )
3. Open in Flatcam: one of the resistor’s pads are missing

See attached image for an overview how it looks like in the different tools.

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Note: I tried this in Flatcam 8.5 and Gerber import works there!

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[Marius Stanciu]

Hi,

Please attach here a simple Gerber file that show the issue so I can have a look at it.
Thank you!

[F.Haskamp]

Example Gerber File

[Marius Stanciu]

Well, it seems that KiCAD is doing a move with pen up to a location followed by a single pen down operation and it expects that to be interpreted as a Flash.

I’ve added this modification to the Gerber parser.
It will be available in the the 8.994 version, when released.

Thank you for the report!

[F.Haskamp]

Thanks for your quick check! Would be interesting to know why it already worked in version 8.5 … ?

[Marius Stanciu]

That’s not so hard to guess. FlatCAM beta has now more differences than similarities with FlatCAM 8.5. It supports more formats and at some point, some changes I made to support some Gerber feature/format, break the old support.

Gerber specifications already have a correct way to describe a Gerber flash (a point exposure with an aperture) and that is using the D03 operation code but KiCAD (and maybe others) used a hack: move with pen up D02 to the flash location and there make a pen-down D01 operation code at the same location, and not moving from there, basically making a line with one point only which of course is a point (flash). Interesting is that KiCAD did used the D03 to specify the non-rotated pad so I guess this is a semi-bug (unorthodox implementation) for KiCAD.

[F.Haskamp]

Thanks for the details and keep up the good work!

[Marius Stanciu]

Fixed in the working copy and the fix will be available in FlatCAM beta 8.994.

[Marius Stanciu]

• Gerber parser - a single move with pen up D2 followed by a pen down D1 at the same location is now treated as a Flash; fixed issue #441

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