Simulation setup for a stellar-blown bubble. The bubble is formed around one or more massive stars inside a molecular cloud, with a 3D Gaussian density profile. The Gaussian thickness σ_x and σ_y in the sky plane is set to 12 pc, while σ_z, which runs parallel to our LOS, is a parameter we vary. The centre of expansion is dislocated from the centre of the cloud by Δr₀, which is another parameter we vary. The dislocation is towards the (−x, − y) direction, perpendicular to the LOS. The molecular cloud is overlaid on a background of atomic gas with the particle density of 4 cm^-3.