Tracking of geometric features. PDB ID 1XCK vs. EMDB ID 1080 (top; GroEL at 11.5 Å resolution) and EMDB ID 1081 (bottom; GroEL at 6 Å resolution). Shown are RMSD values of feature discrepancies observed by (1) naïve vector quantization (Wriggers et al., 2000, black dots), (2) a global deformable model based on IDW interpolation (Rusu et al., 2008, red), and (3) rigid-body multi-fragment model based on Voronoi tessellation (green).