GDS2GBR CSV is a custom conversion software developed to address a problem -- certain small GDSII files when converted to Gerber generate very large Gerber files. Such large Gerber files, approaching 1 GB, can cause the target system to run very slowly or not at all.
These GDSII files consist of a few small cells which are placed in a quasi-array. However instead of using an AREF command (which could be converted to a Gerber SR command) each placement is unique because it is slightly off the ideal array position and it may be slightly rotated.
While GDSII supports placements with rotation, Gerber does not. Hence the Gerber file must be "flat" and the resulting file becomes too large to easily process.
The solution requested is to analyze the hierarchy of the GDSII data and to only produce as Gerber unique cells that are placed multiple times.
The actual placement information is handled in a separate file - a comma delimited file (CSV) that supports X,Y position, rotation and mirroring. The target system can easily process the individual cell data and then uses the CSV information to place the cell as needed in the image area.
Command Line Syntax
gds2gbrcsv input_gdsii output_directory top_structure layers [options] where: gds2gbrcsv full path and filename to the executable gds2gbrcsv.exe input_gdsii full path and name of the GDSII file to process. If spaces or special characters are present surround this argument with "double" quotes. output_dir full path to the output directory where the Gerber file(s) and CSV file will be written. If spaces or special characters are present surround this argument with "double" quotes. This directory will be created so the directory should not already exist. top_structure the name of the GDSII file's structure to start from. If it is the file's top level structure then the argument can be set to = and the program will determine the top level structure automatically. layers specify which GDSII layer(s) to process. use the equal sign "=" to indicate all layers use a list such as +29 for layer 29 (and all its datatypes) use a list such as +29+31 to merge multiple GDSII layers into a single Gerber file. [Options] -h display the syntax help. -min_repeat:VAL minimum number of repeat placements in order to recognize as a repeated cell. Default=2. -overlap:VALUE re-entrant polygons will be converted to "butting" polygons and shared edges will be offset to provide this amount of overlap. Default = 0.01 mm for Gerber files in units of mm and 0.0004 for Gerber files in units of inches. -unit:[mm | inch] units for the Gerber file. Default = mm if mm, default format = 3.5 if inch, default format = 2.6 -format:MN if present overrides the default format. i.e. -format:36 would force Gerber format to 3.6 instead of the 3.5 default. -arcsag:val The chord error to use when "recovering" arcs from the GDSII input. Default = 0.001 mm for Gerber files in mm and 0.00004 for Gerber files in inches. -sort:[X | Y] sort placements in the CSV in increasing order of X or increasing order of Y. Default = X -no_sort disables the sort routine. -workdir:PATH specify a full path to the location where temporary working files are to be written. Surround in double quotes if it includes spaces. -log[:filename] a full path and filename to the log file. If the filename is not specified it defaults to the "output_dir" name. -thrnum:N Number of concurrent threads to use during the conversion from re-entrant polygons to butting polygons and for the computations needed for edge overlap. Number of threads used in arc recovery. -log:filename if present, a log file of the specified name will be generated. -verbose turns on detailed messaging.
Example Command Line
We want to convert a GDSII file called example1.gds which is located in
[Note: there are no line breaks in the command line. They appear here because of formatting needed to annotate each argument.]
"C:\wcad\gbr2csv\gds2gbrcsv.exe" full path to program executable "D:\cad_data\gds2gbr_csv\example1.gds" full path to the input GDSII file "D:\cad_data\gds2gbr_csv\output" full path to output directory = direct program to determine the GDSII file's top level structure +29 convert layer 29 (and all its datatypes) -min_repeat:2 minimum repeat value is 2 -overlap:0.005 overlap butting edges by 0.005 mm "-workdir:D:\cad_data\gds2gbr_csv\working" temporary working files go here -thrnum:4 use 4 concurrent threads
After running our GDSII file through the gds2gbrcsv program we now find in the output directory the following set of files:
The CSV Syntax
Let's annotate the CSV file to explain the syntax.
UNITS, MM UNITS keyword followed by MM | INCH Frame.GBR,1 name of Gerber file followed by # of insertions 0.00000,0.00000,0.000000,N,1.000000 Placement: X, Y, Angle, MirrorFlag, Scale DUMMY_METAL_1.GBR,231 name of Gerber file followed by # of insertions -142.38000,-26.88000,0.000000,N,1.000000 Placement -142.38000,-23.52000,0.000000,N,1.000000 Placement -142.38000,-20.16000,0.000000,N,1.000000 Placement . . . PRDL1_PKG_OOS.GBR,1925 name of Gerber file followed by # of insertions -142.38000,-6.72000,0.000000,N,1.000000 Placement -142.38000,-3.36000,0.000000,N,1.000000 Placement -142.38000,0.00000,0.000000,N,1.000000 Placement . . . PRDL1_D_0_PRSTM_SFT_1.GBR,3645 name of Gerber file followed by # of insertions -139.02139,16.81331,0.027273,N,1.000000 Placement -139.01858,20.16411,359.939381,N,1.000000 Placement -139.01753,-3.34641,0.056608,N,1.000000 Placement . . .
The program issues the following return codes:
|gds2gbrcsv.win32_64.v105.exe||1/31/2017 v1.05 19 MBytes|
gds2gbrcsv v1.05 1/31/2017Bug Fix - Extracting Top Cell
Previous versions had bug in automatically extracting the top level cell when the "=" was used on the command line. Instead, the program looked for a top level cell named TOP. This has been fixed.
gds2gbrcsv v1.04 1/11/2017Bug Fix - Mirror Cell Data
Previous versions could not handle mirrored cell data. This has been fixed.
gds2gbrcsv v1.03 12/20/2016Bug Fix - path names with spaces
Previous versions could not process a file if the name or directory including a space. This has been fixed.
Temporary Scan Files Now Deleted
Temporary GDSII scan files .ssn (created by GDSFILT) were left in the input directory. This has been fixed.
gds2gbrcsv v1.02 12/01/2016-h correction
Corrects the -h display to make the syntax of the -format command clearer.
gds2gbrcsv v1.01 11/26/2016Gerber Output Format
Enables the user to set the Gerber output format statement instead of forcing it to 2.6 for inches and 3.5 for mm.(Note, as this is done at the back end of the conversion, one cannot expect to get more precision in the output than with the previous versions.Verbose Option Added
the command line option, -verbose, has been added to increase detail to the log file.Logging Added
a log file option has been added.Temp File Removal
temporary files that were not previously cleaned up are now removed when the conversion is complete.
gds2gbrcsv v1.00 08/26/2016Initial Release
This is the initial release of gds2gbrcsv.
product ID=92416; no other product ID's needed.
ARTWORK CONVERSION SOFTWARE, INC. Company Profile
417 Ingalls St., Santa Cruz, CA 95060 Tel (831) 426-6163 Fax 426-2824 email: email@example.com