SFGEN Manual

Copyright 2013-2016 , Artwork Conversion Software, Inc.

last update: October 28, 2016 for v2.26

Table of Contents


Graphical User Interface

  Main Dialog

  Advanced Settings

Command Line Syntax




  Distortion Correction




Linux Notes


SFGEN is a preprocessor which reads either GDSII stream files or ODB++ printed circuit board manufacturing data files. It is designed to be used to produce an optimized file for Artwork's Real Time Correction RIP (RTCR). In order to get maximum throughput out of the RIP we rely on the fact that large panels contain repetitive data. The SFGEN program identifies such repetitive data and separates it from the background (or frame) data that is not repetitive. This enables the RIP to effectively place a large number of pixels using bitmap copy as opposed to rasterizing the entire panel by brute force. The output of the SFGEN program is a GDSII stream file (no matter whether the input is GDSII or ODB++) and it has a limited hierarchy optimized so that the RIP need do as little rasterization as needed.

Graphical User Interface

Start up SFGEN

The main dialog will appear:


Use the Open button to select (open) either:

    a GDSII stream file (select File radio button)

    an ODB++ file in .tgz format (select File radio button)

    an ODB++ data hierarchy (select Directory radio button)

    Read Only - if checked, SFGEN does not modify the contents of the input directory (for ODB++) and makes a copy. This may take more time if the ODB++ data is large.

Once you have selected the file, SFGEN will scan it, verify it is OK and will provide a list of Steps/Layers (for ODB++) or Cells/Layers (for GDSII) for you to select when running the conversion.

Output File

    Use the Browse button to select the location of the output stream file and its name.

Output Layer

    Select the layer you want your data to appear on for the output GDSII file. If you don't select any particular layer it will defaul to layer 0. (Only applies for ODB++ input; for GDSII input it matches the selected input layer.)

Output Cell

    Select the name of the top cell (structure) in your output GDSII file. If you do not make an entry it will default to TOP. (Only applies to ODB++ input; for GDSII input, the output cell matches the cell selected from the input.)

View Output

    Once a file has been converted this button will go from gray text to black indicating it is active. Clicking on it will launch a GDSII viewer (specified in Advanced -> Settings) to display the output.


    This list will show the available steps in the ODB++ file. You must select one of the steps (cells) - typically the user will select the top level Step (often named panel or array) which contains references to arrays of circuit steps.

    For GDSII input, the list will show the "top" level cells only. (It is possible to process a non-top level cell for GDSII input using the command line.)


    ODB++ and GDSII files generally contain many layers; however it is normal to rasterize only one of these layers per image. Therefore one should select the layer to process. If the user selects more than one layer:

      a) for ODB++ input, only a single layer may be selected.

      b) for GDSII input, the layers selected will be merged.


    Clicking on the Convert button will start the conversion.


    Clicking on the Advanced button will open a tabbed dialog enabling the user to control Settings, Transformation, Annotation and Distortion.


In the example below the user opened the ODB++ file called: 226.tgz and selected the step called "array" and selected the layer named "top".

Advanced Configuration

The advanced configuration is a tabbed dialog that enables the user to control the conversion settings, to define transformation, to define text annotations that will be dropped into the raster output and to load a distortion data file that can be used to compensate for distortion in the substrate.

Settings Tab

Working Dir

    The directory where temporary files are stored on disk.

Thread Num

    The number of concurrent threads to use during processing. Do not exceed the number of CPU cores. Do not count virtual cores created by hyperthreading.

Optimize SR

    Programmers - please provide details on this option.

Show Progress

    If checked, a progress window/bar is displayed as the program runs. For large and complex files, showing progress may slow down the overall conversion time.

Keep Temp

    If checked, temporary files in the working directory are not erased after completion. Useful when debugging. Also, if this option is checked, the user will find a script file in the working directory that can be used to run SFGEN from a command line. As the script is quite complex, this is the recommended way to obtain a prototype batch file.

Open Args

    Special arguments passed to the engine responsible for opening the input data. Only used for debugging.

Arc Resolution

    When converting from ODB++ to GDSII this controls how arcs and circles are broken into segments.

Chord Error

    When converting from ODB++ to GDSII this controls how arcs and circles are broken into segments.

User Grid

    sets the grid for the output GDSII. Typical values are 0.001 or 0.01. Coarser grids may result in a loss of precision.


    a small random value (all directions) added to the repeating output cells. Intended to reduce moire patterns. Special function for a specific user.

Max Points

    The maximum number of vertices per boundary in the output GDSII file.


    Instructs the program to use cut-lines instead of "butting" slices for polygons with islands. Do not use this option if you are also using the distortion function as it may result in illegal polygons in the output. This option is only present for testing purposes.

Processing Flows

There are three data flows that can be selected for GDSII. LCD for GDSII input and large LCD panels; GDSCompact for rasterizers that need convex quadrilateral boundaries to achieve maximum performance; Panel for ODB++ PCB layouts that contain arrayed circuits.

LCD Flow and Parameters

    need a detailed description from the programmers

Panel Data Flow and Parameters

    need a detailed description from the programmers

GDSCompact Flow and Parameters

    need a detailed description from the programmers

Convert Args

    Command line arguments for the conversion engine are entered here. Normally this is left blank; the only time such arguments are needed is during testing and debugging.


    Enter the path and executable of a GDSII viewer. When clicking the View Output button, SFGEN will call this program passing the name of the GDSII output file.

    Example: c:\wcad\qckvu3\qckvu3.exe

Transformation Tab


    Enter the DPI that the RIP will use. This value (in conjunction with the buffer size) is used to determine the size of the repetitive geometries so that the RIP will have an optimum input.

Buffer Size

    Enter the buffer size (this value is used in conjunction with the DPI) that the RIP will use to hold the repetitive data. This is not the raster buffer size but a separate buffer dedicated to holding the bitmap masters. Programmers - how do these settings interact with the span length parameter if they do interact at all?

Scale X

    Enter the scale X factor and the anchor coordinate. See Reference

Scale Y

    Enter the scale Y factor and the anchor coordinate. See Reference

Mirror X

    Check to enable mirror X (i.e. X -> -X) also enter the anchor coordinate. See Reference

Mirror Y

    Check to enable mirror Y (i.e. Y -> -Y) also enter the anchor coordinate. See Reference


    Enter a Rotation value in degrees (increasing angle is CCW) and an anchor point about which the input data is rotated. See Reference

Shift (X,Y)

    Enter the shift along X and Y.

Offset (Edge Bias)

    Select the offset mode: NONE, INNER, OUTER, BOTH. See the reference section for details as to how INNER, OUTER and BOTH are implemented. Reference. Programmers - there appears to be a new option called Random Sizing. Please provide documentation on what this function does and why it has been added.

Order of Transformation

The transformations are performed in the following order:
  1. Scaling
  2. Mirror X
  3. Mirror Y
  4. Rotation
  5. Translation (Shift)

all units are in microns except rotation which is in degrees

Annotation Tab

This tab enables the user to load an annotation file. The annotation file contains one or more annotation entries that instruct SFGEN to generate text (or to "annotate" the mask.) This text is usually some sort of an identification, lot stamp or date stamp associated with the actual writing of the mask.

If the Add Text check box is selected, the user should also select an annotation file by using the Browse button. (Checking the box and failing to select a legal annotation file will cause a conversion failure ...)

The annotation file can be created by hand, by an application or by a Qckvu3 plug-in.

The syntax and details of the annotation file are here.

Distortion Tab

Distortion refers to a correction applied to the CAD data in order to warp the CAD data so that it "fits" on a substrate that may have been subject to some physical distortion due to either temperature or possibly processing (such as etching one side). Distortion can be corrected either in the SFGEN program or it can be corrected in the RTCR.

The correction works by reading the coordinates in a table of common points from both the CAD data and the measured on the substrate. These points drive a correction engine that attempts to match the distortion found on the substrate. Of course, there is no guarantee that the distortion can be exactly matched from only a relatively small number of data points.

See the reference section for details and examples.

Use Correction File

If checked, SFGEN will read the user specified correction file and apply corrections to the output file. Use the browse button to select the appropriate text file containing the coordinates.


A value (in microns) used to determine whether an instance of a cell is equivalent to other instances. If this value is set too small, each bitmap placement will require its own definition and the RIP will not run very quickly. See the reference section on distortion to understand how the tolerance affects repetition and RIP throughput.