Fig. 2

Example micro-CT images, acquired for grid characterization, of spheres with a high fillable-volume fraction (FVF) of 59% and b low FVF of 27%. The printing inaccuracies with respect to the design were observed at the sharp edges of the grid crossings and were fractionally higher for the denser grids (low FVF). c Segmented mask of one sphere, including ROIs used to calculate the area ratio for central (ROIs 1–5) versus peripheral (ROIs 6–9) voids as a metric of the geometric variation of printing inaccuracies