OTOY Forums

That sounds a bit generic. I do not mean fluid simulations, I just need a static picture. A simple thing:

A drinking glass, thick walled, made of glass ... say a whiskey glass etc. How do you put the whiskey in there? A complete, second object, that just firts the glasses inner volume perfectly, surface of the "whiskey" object laying directly on top of the "glass insides" surface? Or can you just add a planar surface to the glases inside, not using a seconf object, and give that liquid surface whiskey material, and the renderer "Knows" it has a volume made of whiskey below it?

I'm very confused on how renderers decide if something is "inside" or a volume and how they act then. I never have trouble with nontransparent stuff .. you just don't care about anything inside and only work with an outside. but I get quite confused when I have glass involved and "insides" etc.

Typically, in order to get the proper look, the liquid needs to be a separate closed mesh volume that slightly overlaps the glass mesh. If it doesn't intersect, you will not get the correct refraction effect of the liquid/glass. You could accomplish this by selecting the inside polys of the glass up to the level of where you want the liquid to be, copy those polys into a new mesh, scale it up just a little bit, and then close the top off. Once that's done you can sculpt the top if it needs splashes or waves.