How to model a liquid in glass in Corona?


The correct way to model a liquid in glass is to duplicate part of the container's inside, cap it, and make it slightly bigger than the inside of the container. In Corona, this is the correct workflow for such scene and there is no need to use multi/sub materials or flip normals of the liquid mesh like in some other renderers. 




Examples


a) Liquid mesh perfectly overlaps the faces of the inside of container mesh - this produces wrong results






b) Liquid mesh is slightly bigger than the inside of container mesh - this is the correct method







c) Liquid mesh is slightly smaller than the inside of the container - this produces wrong results