Images at λ = 2.3, 4.5, and 12.1 μm (left, middle, and right panels, respectively) of the 10 AU inner regions of the axis-symmetric envelope (Sect. 5.2) and computed from the DGFEM solution with the ray-tracing module (Appendix C). The top, middle and bottom panels correspond to the inclinations i = 12.5, 77.5, and 90 deg, respectively. The colour code shows the specific intensity value (in W m⁻² Hz⁻¹ sr⁻¹) of the envelope $I_v^{\text{env}}$, inside each pixel. The solid white lines show the iso-contours of $I_v^{\text{env}}$.