Limb brightening factor and projected shell FWHM assuming a bubble geometry with a radius of 6.5 pc for the total intensity of RCW 79, based on the formalism in Kabanovic et al. (2022). To be a self-consistent spherical bubble, the deduced geometric shell width from the limb brightening and the projected shell FWHM must be the same within the error, which is not the case. This shows that the emission distribution of RCW 79 is not consistent with a spherical shell morphology. In this plot the results for the highest projected shell FWHM (1.8 pc and 2.3 pc) were not included as the FWHM formalism does not allow a solution for these values.