As you move along, the filament changes in diameter will cause the 3D printer to over- or under-extrude filament. Winding precision is a visual test where I check to make sure the filament works well on the spool, without any crossovers that can cause snags while printing. The nature of the printing process makes any clear plastic misty and infill makes it blurry as well. They are custom pieces and cost between 70,000-80,000 yuan (U$10,000-11,500) each.