Normalized intensities of major axis and minor axis cuts of the IRAS4A1 RADMC-3D models. Top panels: scale height of each model was fixed to H/R = 0.3. Middle panels: Ψ flaring index values were fixed to 1.3 in the RADMC-3D models. Bottom panels: scale height was fixed to 0.3 and flaring index to 1.3, but the gap width was reduced in each model. The “shoulder” shape and the asymmetry of the disk are better reproduced using a large scale height, a large flaring index, and a small gap width. Unfortunately, an excess of emission is found in the models and the small size of the gap needed cannot be observed at the current resolution.