The operation Compress compacts the structure in Z-direction by the value entered in Compression Fraction. Values must be between 0 and 1, where the extremes (0 [0% compression] and 1 [100% compression]) are not feasible.

For instance, a value of 0.6 (60%) compresses the structure to 40% of its original thickness in Z-direction.

This is shown in the next example, where the structure size in Z-direction is reduced from 200 voxels to 80 voxels.

If analytical data was present before, this information gets lost after the compression.

Compression Algorithm

The compression algorithm is purely geometrical. Each Z pillar is compressed independently. All connected components in the pillar are placed nearer to each other according to the compression fraction. They do not overlap. When only one connected component is left, and the structure should be further compressed the pillar is scaled down and the mass is no longer preserved.

The algorithm is illustrated below: a pillar is “cut out” from the structure, and the two connected components are assigned to different material IDs only for visualization (Reassign). Then, several compression steps are performed: Observe how the solid components move closer to each other while they keep their original size. Once they touch and no empty voxels are left, the component shrinks (see last step).