ArchiCAD for Mac Geometric Description Language file
File type: Source code and script file
An .isym file is a binary Geometric Description Language (GDL) data file used by ArchiCAD for Mac.
The file may contain one or more text tags and belongs to ArchiCAD's parametric object system.
File type category:
Source code and script file
Date updated: September 30, 2026
GDL (Geometric Description Language) is Graphisoft's parametric object-definition language, created for ArchiCAD and used in other applications. It can define a 3D model, 2D model, property data, user interface and parameter handler. These definitions can be parametric.
A GDL object acts as a container for GDL scripts, default parameters, optional binary data and additional information such as a preview image. An .isym file contains GDL binary data and may also contain one or more text tags.
This format is associated with the Mac version of ArchiCAD, Graphisoft's architectural design software. ArchiCAD is also available for Microsoft Windows. MIME types associated with GDL include model/vnd.gdl and model/vnd.gs.gd.
Open an .isym file from within a compatible version of ArchiCAD. Because it contains binary GDL data, it is not intended to be opened as a normal text document.
Older files created for ArchiCAD for Mac may require the original or a compatible ArchiCAD release. On Microsoft Windows, try the installed ArchiCAD version, although support for an older library file may depend on the software version.
The file is a component of ArchiCAD's GDL object system rather than a document format intended for independent conversion.
To preserve or reuse its contents, open or migrate the associated object or library in a compatible version of ArchiCAD and save it using the formats supported by that version.
Software applications that handle other tasks involving isym files:
Microsoft Windows
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