Below should be concise enough legend of the calculation assumptions. The tortuosity is defined as the ratio of the actual (red) path to macroscale (black) path, calculated as a distribution by considering every entry point available in the entry surface. The connectivity neighborhood is assumed to be 6 nearest neighbors, as most FEM or FVM simulations will have the same connectivity.
[TD]=Tort3D(Alpha) finds the tortuosity distribution of a properly weighted 3D dataset Alpha. Every voxel in the dataset Alpha must have a value representing the tortuosity of the phase that the voxel represents. TD is a list of calculated tortuosity values.
[TD Tormap]=Tort3D(Alpha) will also generate a non-unique visualization of the calculated paths.