俱舍論疏 11.137

11.137

論「然下眼不能至要作下地化」，明下地眼不能得見上界地色，及身不觸異地觸，以別地繫麁細異故。若上地身下地，下地不能為礙，故作化也。

The Commentary states, "From 'However, the lower eye cannot' up to 'must necessarily create an apparition of the lower plane,'" explaining that the eye of a lower level cannot see the forms of a higher realm or level, and the body does not touch the tangible objects of a different level, because the coarseness and subtlety differ according to the bonds of different levels. If a body of a higher level descends to a lower level, the lower level cannot obstruct it, and therefore it creates an apparitional form.