Operating system: Mac OS
Slicer version: 4.8.1
Expected behavior: I saved my tumor segmentation as a nrrd file or seg.nrrd file and open them in other tools (MRIcron, matlab).
Actual behavior: I found the location information was lost, the size of the matrix was the max diameter of the tumor, but without the blank background.
Segments are correctly positioned in physical space. By default, blank voxels are stripped to conserve memory (image origin is updated accordingly to ensure the correct position is maintained).
If you work with software that cannot take into account image origin, spacing, and axis directions and just rely on matching of voxel coordinates (or the software cannot handle overlapping segments stored in 4D volume), then you need to export the segmentation to a labelmap node: