GeoDict structure files in GDT format contain voxel structures. They store information about the materials in the structure and each voxel in the structure is assigned to one of the materials. With GeoLab, it is possible to load such a GDT file in MATLAB, modify it, and save changes for later visualization in GeoDict. Also, analytic object data can be contained in a GDT file and can be accessed and modified in GeoLab.

Since GeoDict 2023, 256 different materials (with IDs from 0 to 255) can be handled, where ID0 usually stands for the background material. GeoLab allows also to set material IDs from 0 to 255.

GDT files are compressed to save space on the hard disk and to allow faster loading and writing speeds in GeoDict. When loading them to GeoLab, they need to be unpacked, when saving them, they need to be packed again. This is done automatically, so you usually don’t need to take care of this.

GeoLab’s GDT class allows to load and edit GDT files. All properties of the GDT class, like the number of voxels in each direction, voxel length, etc. can be accessed. It is possible to edit the domain size as well as the structure data or part of it. Furthermore, it is also possible to change the constituent materials.

The capabilities and properties of the GDT class are explained in detail in the GeoLab documentation in MATLAB.