Variation of Ω_p as as function of the reference frame orientation Δϕ. Results for the B5 and KRATOS simulations are shown in the upper and lower panels, respectively. Results of the IPTW method are shown as open symbols, while those of the LTW method are drawn as a solid line (for the i = 45° case, upper panel), and as dotted, solid and dashed lines (for the i = 25, 45 and 75° cases, lower panel). Horizontal dashed green lines are the ground-truth bar pattern speeds. The vertical orange (navy) vertical line corresponds to the frame orientation where the x-axis of the disc lies along the major axis of the bar (y-axis, respectively).