- If your 3D structure is voxelized you can define a similarity index like binary cross-entropy to see how correlated they are. https://en.wikipedia.org/wiki/Cross_entropy
- Also, if you want to compare two meshes, check this thread on researchgate, it probably gives you the answer. https://www.researchgate.net/post/What_kind_of_metrics_can_I_use_to_compare_two_3D_surfaces