Visibilities at the peak of the Brγ, Na I emission lines and continuum emission towards IRAS 17163 overplotted with simple geometrical Gaussian models. Na I and continuum emission follow very similar distribution. Na I shows a smaller drop in visibilities compared to Brγ, indicating that Na I stems from a smaller emitting area compared to the Brγ. The AMBER dataset was rebinned to match the spectral resolution of GRAVITY. A period of 5 yr indicates a shrinkage of the Brγ emitting region to half its size.