File Formats


GDSII is the de-facto industry standard for mask drawing and layout design. GDSII is a binary format that is platform independent, because it uses internally defined formats for its data types.


The Drawing Interchange Format (DXF) enables the interchange of drawings between AutoCAD® and other programs. DXF files can be either ASCII or binary formats.

LinkCAD is compatible with all versions of the DXF format and has full support for REGION entities.

Gerber RS-274X
(Gerber Option)

Gerber RS-274X is the most commonly used format for photo-plotting applications.

LinkCAD has full support for aperture macros and layer polarity in Gerber RS-274X files.

PDF and PostScript®

PDF and PostScript®/EPS  are the industry standard for sending documents to high-resolution printers.

LinkCAD's PostScript compatible export has been optimized for producing low-cost masks using high-resolution laser printers. The PostScript export can also be used to print your layout for documentation purposes.

LinkCAD relies on two external tools to import PostScript: pstoedit and Ghostscript. These tools are distributed under the GNU General Public License. We distribute a setup program that installs both tools, but you can use your own versions of these tools, as long as they exhibit the same command line interface.


CIF is mostly used at universities for mask drawing and layout design. LinkCAD is the only program to import and export all known variations of CIF.

LinkCAD supports an extension to the CIF format, called Cle CIF2.0+. These are special instructions that add donuts and symbol scaling to CIF. Cle CIF2.0+ is only used by the CLE layout editor on the DOS and Windows platforms (WieWeb Software, Borne, The Netherlands).

(GDS-TXT option)

GDS-TXT is a human-readable version of the GDSII file format. It is not meant for exchanging CAD data with other programs, but it allows you to write the drawing data in text form. GDS-TXT files can be opened and edited with a text editor, and the result can be read back into LinkCAD.

Bitmap Image Files

When dealing with graphic images, there are two types: either bitmap, or more correctly raster, and vector. Vector images refer to images that are made up of lines that are described mathematically. Raster images, on the other hand, are made up of a grid of dots, or pixels, each containing color information.

CAD software uses vector based image formats, such as DXF, GDSII or CIF. LinkCAD can import raster image files, such as your company logo or a photograph, and convert it to vector format. Each pixel is translated into a square polygon, and adjacent polygons are merged.

LinkCAD supports both, import from and export to bitmap image formats PNG, JPEG, BMP or TIFF.

(3D Modeler Option)

ACIS is a 3D solid and surface modeling library, published and marketed by Spatial Technology, Inc. It is used by a number of popular modeling programs as their primary modeling engine. The native file format of ACIS is called SAT and applications that incorporate ACIS can import and export it. ACIS data may also be embedded in DXF or DWG files. This is done by directly importing SAT files or by importing DXF or DWG files that contain ACIS entities.

LinkCAD extracts 2D planar geometries from 3D ACIS files.

Parasolid XT
(3D Modeler Option)

Similar to ACIS SAT, Parasolid is a geometric modeling kernel originally developed by Shape Data Limited, now owned and developed by Siemens Digital Industries Software. It is used by a number of popular modeling programs as their primary modeling engine.

LinkCAD extracts 2D planar geometries from 3D X_T files.

(3D Modeler Option)

STEP (Standard for the Exchange of Product Data) is a popular neutral 3D CAD file format that is interoperable among various CAD programs such as CATIA®, Creo®, SolidWorks®, NX®, Inventor®, and others.

LinkCAD extracts 2D planar geometries from 3D X_T files.


Scalable Vector Graphics (SVG) is an XML-based vector image format for defining two-dimensional graphics, having support for interactivity and animation. The SVG specification is an open standard developed by the World Wide Web Consortium (W3C) since 1999.

SVG images are defined in a vector graphics format and stored in XML text files. SVG images can thus be scaled in size without loss of quality, and SVG files can be searched, indexed, scripted, and compressed. The XML text files can be created and edited with text editors or vector graphics editors, and are rendered by the most-used web browsers.

ASCII (Text) Data

LinkCAD supports a very simple text-based format for importing polygons. This allows you to quickly convert graphical data in tabular form into any of the supported file formats.

Zeland IE3D

The IE3D Format is a text file that defines the graphics for the IE3D 3D Electromagnetic Simulator by Zeland Software. The file structure does not support hierarchical levels and has a file extension of .GEO.

File Structure
Both two-dimensional and three dimensional polygons and interconnects (wires) are defined as X, Y & Z coordinates. Electrical attributes for the polygons and dielectric materials are defined in the file. Ports are also defined as well as grid structure, cell size and frequency range. When a file is transferred in or out of the IE3D format, all attributes are lost. This is not a problem, because they are easily added within the IE3D modeler or when exported, the attributes are not used.

Data Format
All geometries are defined as polygons with at least three vertices for each polygon. There are no limits to the number of vertices in a polygon. Layers are defined in the Z axis with an unlimited number of layers supported. Each vertex of a polygon has an X, Y & Z coordinate assigned and are on a separate line, which makes it quite easy to read with a text editor.

Compass Layout

Compass is a commercial VLSI design tool by Compass Design Automation. It uses .ly files as its native format to describe the design geometry in terms of symbols, symbol references and polygons.

Compass Layout uses one file per cell; a complex layout will therefore consist of several .ly files.

Sonnet Software

Sonnet Software provides commercial EDA software solutions for high-frequency RF/MW EM (Electromagnetic) analysis of:

3D PLANAR Circuits
Planar Antennas


TLC is the file format used by the LASI layout editor, a free program distributed under the GNU General Public License. TLC uses one file per cell; a complex layout will therefore consist of several TLC files in one directory.

For more information, see the WinLASI homepage.


Ansoft Neutral Format is used for finite element modelling. Ansoft was acquired by ANSYS™ and, therefore, the Ansoft Neutral file format is also known after that time as the ANSYS Neutral file format.


MODLA is a IBM internal CAD format.

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