All panels: squared, normalised visibilities V² against baseline in Mλ. The yellow circles show the 1.67μm data of HD 100453 from the PIONIER Herbig Ae/Be survey (Lazareff et al. 2017; Kluska et al. 2016). For this analysis, only the short baselines are of interest (brightly coloured symbols). The red line shows our best model, S18C100K. Top panels: we show the effect of different QHP sizes (green: S18C250, red: S18C100K, blue: S18C500K and yellow: S18C1.6M) and scale heights (yellow: S10C100K, red: S18C100K, blue: S35C100K). Lower left panel: the QHPs lead to a drop (albeit small) even without the presence of a gap. Lower right panel: we show the effect of quantum heating. For the model corresponding to the blue line, S18C100Knqh, the grains behave like conventional dust. The drop at short baselines vanishes.