The Ziggerins are artificial objects composed of a small number of primitive volumes. There are 6 "classes" that differ from each other in the composing parts and the general structure, representing six different basic-level categories. Within each class, 12 Ziggerins share a similar basic structure and differ in "style", or the detailed manifestations of the parts. The 12 styles are formed by variations of parts along three dimensions: (1) cross-section shape (round, octagon, or square); (2) cross-section size change (constant or varying along the principal axis); and (3) aspect ratio of the cross-section (thin or thick). Recognition of Ziggerins within a class thus represents subordinate-level individuation.
Wong, A.C.-N., Palmeri, T.J., & Gauthier, I. (2009). Conditions for face-like expertise with objects: Becoming a Ziggerin expert – but which type? Psychological Science, 20(9), 1108-1117.
There are 2 object sets, amoeboid and regular ones. For each object there are 5 views (separated by 20 deg for amoeboid and 28 deg for regular objects). The amoeboid set contains 62 objects, 31 of which have parts occluded at certain views (e.g., oam01_n20.pct) and 31 have all parts revealed at all views (e.g., nam01_n20.pct). The regular set contains 80 objects, 40 of which have parts occluded at certain views (e.g., ore1_1.pct) and 40 have all parts revealed at all views (e.g., nre1_1.pct).
Wong, A.C.-N., & Hayward, W.G. (2005). Constraints on view combination: Effects of self-occlusion and difference between familiar views. Journal of Experimental Psychology: Human Perception & Performance, 31, 110-121.