Creating a truly photorealistic asset in any 3d package is a skill that requires a lot of attention to detail. It’s not just about understanding the physical properties of an object , but how to model the object in a way that allows the renderer to translate the data into pixels that convince us of its existence. Most of the time, our 3d models should exactly replicate real life, but sometimes, achieving photorealistic results means bending the rules a little. A glass of liquid is a really good example here, and prompts one to highlight how a renderer such as Arnold, deals with the scenario, and favours a particular workflow.