GrainGeo always saves the generated structure as a GeoDict structure file (Structure.gdt). The file is placed in an automatically created result folder inside the chosen project folder (File → Choose Project Folder... in the menu bar).

An additional option to save generation data, is to check Save Random Field (*.gvf) to also save the generated stochastic field in the result folder.

This random field can also be loaded from the result file in the Result Viewer.