What Is an SZN File?

A file with the SZN file extension is a HiCAD 3D CAD file. It’s used by the computer-aided design software called HiCAD to store 2D or 3D drawings.

How to Open an SZN File

SZN files can be opened with ISD Group’s HiCAD. The program isn’t free to use, but there is a demo you can download that should also provide the same support for these files. The free HiCAD Viewer, also from ISD Group, can open SZN files too, but only if they contain shaded 3D models. This means 2D models or glass models that are saved in the SZN format can’t be opened with the viewer. If you suspect your file has nothing at all to do with HiCAD or CAD drawings in general, try opening it with a free text editor. If the file is full of just text, then your SZN file is just a text file that can be used normally with any text editor. If most of the text is illegible, see if you can pick out something identifiable from the mess that can help you research the program that created your file; it’s usually also the same program that can open it.

How to Convert an SZN File

HiCAD Viewer can save open files to a different format. It’s likely that you can use that program to convert the SZN file to some other similar CAD-related format. The same goes for the full HiCAD software. There’s most likely an option for conversions in the File or Export menu.

Still Can’t Open It?

If your file doesn’t open as described above, there’s a good possibility that you’re just misreading the file extension and confusing a different file for one with the SZN file extension. For example, this extension is very similar to SZ used by the Winamp music playing software as a custom interface, or “skin.” The two formats have nothing to do with each other, even though it’s easy to mix up their file extensions. Here are some other examples:

ISZ: Zipped ISO Disk Image file SZS: Video game data file SZ4: E-triloquist Phrase Library Format file

If you discover that your file is in none of these formats, research the real file extension to see which programs can be used to open or convert it.