Gerber Paser Error

[tgob]

I'm having problems importing an Eagle gerber 274x file into UVTools 5.0.3 x64 running on Windows 11. The file shows up fine in Gerber View and other software. The file is in inches which I understand is a potential issue. Is this causing the problem?

When I attempt to generate the PCB image I get the following error message:

System.Data.SyntaxErrorException: Syntax error: Missing operand after 'X0' operator.
at System.Data.ExpressionParser.Parse()
at System.Data.DataExpression..ctor(DataTable table, String expression, Type type)
at System.Data.DataTable.Compute(String expression, String filter)
at UVtools.Core.Gerber.Primitives.PolygonPrimitive.ParseExpressions(String[] args) in UVtools.Core\Gerber\Primitives\PolygonPrimitive.cs:line 118
at UVtools.Core.Gerber.Apertures.Aperture.Parse(String line, GerberFormat document) in UVtools.Core\Gerber\Apertures\Aperture.cs:line 113
at UVtools.Core.Gerber.GerberFormat.ParseAndDraw(GerberFormat document, String filePath, Mat mat, Boolean enableAntiAliasing) in UVtools.Core\Gerber\GerberFormat.cs:line 271
at UVtools.Core.Gerber.GerberFormat.ParseAndDraw(PCBExposureFile file, Mat mat, SizeF xyPpmm, MidpointRoundingType sizeMidpointRounding, SizeF offset, Boolean enableAntiAliasing) in UVtools.Core\Gerber\GerberFormat.cs:line 544
at UVtools.Core.Operations.OperationPCBExposure.DrawMat(PCBExposureFile file, Mat mat) in UVtools.Core\Operations\OperationPCBExposure.cs:line 326
at UVtools.Core.Operations.OperationPCBExposure.ExecuteInternally(OperationProgress progress) in UVtools.Core\Operations\OperationPCBExposure.cs:line 367
at UVtools.Core.Operations.Operation.Execute(OperationProgress progress) in UVtools.Core\Operations\Operation.cs:line 790
at UVtools.UI.MainWindow.<>c__DisplayClass114_0.b__0() in UVtools.UI\MainWindow.axaml.cs:line 2597

The I've attached the cmp.gbr file.

Any advice or assistance would be much appreciated.
cmp.zip

[sn4k3]

On your gerber file it has: 5,1,8,0,0,1.08239X$1,22.5*
The problem is on 1.08239X$1, I never saw that anywhere, that is to be the diameter. X represents a value separator. However documentation never state the use of X on the primitive.
My guess is that 1.08239 is the default diameter if $1 is not provided, otherwise $1 will be the diameter. But i'm not sure...

To fix your file you can simply replace that line with: 5,1,8,0,0,$1,22.5* as default is never used, however I found a bug on vertice count definition, which may not render the polygon.

[tgob]

Thank you for your very prompt and helpful reply Tiago. I’ll have a go at fixing this by manually editing the file, but first I’ll try and understand what the offending line is actually doing. Much appreciated. Dear Tiago, I’m making progress on this thanks to your advice. I can now get an image on my Elegoo Saturn 2 LCD (see attached). This is really hard to photograph as the UV is very intense. There are a few issues that still need to be resolved. 14 pads are missing and there are ten alias lines. I think these are not a coincidence. I figure this is down to the line modification. I haven’t yet researched this. I’m working on it. There are also a number of pads that are showing up as ellipses when they should be slots (rectangular bodies with semi-circular ends). The immediate fix is to change the pad geometry to semi octagonal ends. I’ll report back on this. As an aside I’ve been using your excellent program for some time. I’m retired and have limited means, but I do link to your tool on my own website: https://turtlesarehere.com/html/elephant-s-foot.html. t.

[sn4k3]

You can try the new version

[tgob]

Yes, I am confident that the syntax is correct based on the attached official Standard published by Ucamco.

I have been unable to locate the EIA Standard but I understand that this is RS274D and has been withdrawn.

Refer to the table at the top of page 67 of the Ucamco (formerly Barco ETS) Standard. This specifically allows an upper-case X as a parameter modifier (multiply) in the AM command. Refer also to the operators on page 20 of the Barco earlier Standard.

The examples show exactly how these can be used within the AM command to apply variables, modify constants, and redefine variables within the parameter block.
RS274X AM Barco ETS.pdf
RS274X AM Ucamco.pdf

[tgob]

I've just tried the new version (5.0.4). The obrounds are working perfectly. The octagonal pads are now imaging at the correct size but there is issue with the rotation parameter (22.5, in degrees) as the pads are not being rotated.

[tgob]

Thank you for your efforts on this Tiago. Attached is an image showing the rotation issue with the octagonal pads.

[sn4k3]

Thank you for your efforts on this Tiago. Attached is an image showing the rotation issue with the octagonal pads.

Send me that Gerber so I can test.

[tgob]

As requested. rename from .txt to .gbr
sol.txt

[sn4k3]

UVtools uses aligned polygon shapes while gerber uses raw polygon shape, to temporary fix this use 0 as rotation.
Also keep in mind you should use printers with square pixel pitch for PCB engrave, otherwise you will have problems with polygon and regions

[tgob]

Yes, this worked Tiago and, after I’ve made a few adjustments to the board layout I can continue with my actual exposure experiments and complete a tool-chain for accurate alignment of double sided boards. As an aside many PCB CAD packages (including my own rather antiquated but perpetual licensed version of Eagle) are quite restrictive on rotation, often limited to 90 degree increments. While not fully implementing the Gerber Standard this would allow UVTools to use just two primitives for pad shapes that are self symmetric in either X or Y (for example the octagon). Thank you again. t.

[sn4k3]

Check the new version

[tgob]

All fixed! Thank you so much for attending to this. I’ll write up my toolchain and alignment process and share it with you once it’s complete. UVTools is now a turn-key solution (no editing Gerber files) to my PCB process without endless attempts to print positives on Mylar film with a laser printer.

[tgob]

Dear Tiago, I just went to make a donation of 50 Euro for your support and responsiveness but New Zealand is somehow blocked from credit card donations to you. Can you let me know if there is an alternative way of contributing? If this won’t work then maybe I can donate the same amount to a NZ charity of your choosing? t.

[sn4k3]

I have no set restrictions. I think you tried via paypal? On UVtools go to Help -> Donate there you can find two ways to donate, both accept credit card, try the other method you didn't before.