Archive for July, 2008

Linux: AutoCAD DWG to SVG preview conversion.

TechnologyYears ago I did a small utility to convert DWG or DXF files into a vector-graphic, zoomable, SVG preview. The Linux command-line utility was used in a larger drawing management application that I had built before I left that company for greener pastures.

The Linux server-based application would scan the vast (100,000s of CAD drawings) and, depending on their format, attempt to create thumbnails and extract textual information from them and populate a database so we could easily find related drawings through a simple web-interface.

CAD File The software would present thumbnails of the drawings; when the drawing was in DWG or DXF format, the thumbnail would be an SVG vector representation of the original drawing instead of an image. That made the preview much more useful as you could zoom in and still retain enough detail to ascertain if the drawings was actually what you were looking for.

Other file formats (TIFF, HPGL plots, etc) were transformed into PNG image previews that were saved into 2 size: a small thumbnail, good enough to be displayed in a list, and a larger one that would show more details.

The server software was written in Perl, with some of the converters in C. Every night, the server would go through the whole tree of drawings on the filesystem, looking for drawings it hadn’t seen before and it would pass them to the appropriate plug-in for extracting text -where possible- and create thumbnails.

A few years ago I put a cad2text and cad2text Linux utilities on my older technical site and recently someone1 contacted me to request a small update. So if anyone is interested in these things, they can still get the tools.

Memories of fun projects…


  1. Jorge from the University of Toronto is using cad2svg in a WiFi positioning project.
    Thanks Jorge! 

Add comment July 18th, 2008


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