The geometric accuracy of the formed parts was explored as a function of two key toolpath parameters, namely, the incremental depth and the relative position of the supporting tool. In DSIF, the squeeze factor s (Fig. 6(a)) indicates the magnitude of squeezing within the local area between the tools, while the surface normal is used to orient the tip of the supporting tool with respect to the forming tool, or top tool. When s = 1.0, the bottom tool is just touching the sheet and when s < 1.0, the top tool and the bottom tool are actively squeezing the sheet metal. Values of s = 1.0, 0.9, 0.8, 0.75 were used in DSIF and in the D-stage of MDSIF to study the effect of sheet squeezing on the achievable geometric accuracy. The position of the tools in ADSIF and A-stage was defined via two parameters D (distance between the axes of the two tools) and S (vertical distance between the bottom of the sheet and the tip of the bottom tool), which were fixed at 2.5 mm and 0.43 mm, respectively (Fig. 6(b)). The geometric accuracies of the parts formed by MDSIF were compared to that achievable with DSIF and ADSIF toolpaths using a low incremental depth of 25 μm and a high incremental depth of 100 μm. The D and S values for ADSIF were obtained from the previous work  since they yielded the best possible geometric accuracy. In MDSIF, the same incremental depth was used for both the A-stage and D-stage. Additionally, MDSIF was also performed using an incremental depth of 80 μm, 100 μm, and 120 μm. For all toolpaths, a spiral tool motion strategy was used since it has shown a better geometric accuracy as compared to contour toolpaths, which is illustrated by the comparison of cross section profiles of the inner surface (Fig. 4). The specifications of the experiments are summarized in Table 2, where b is the base time, to which every process is compared, and equals to 7 hrs under the previously set forming speed (5 mm/s).