Cool off with a refreshing beverage

The third and final item in our Visual Development texturing project is a glass bottle with a drink inside. This builds a lot off of what we learned with the box from the previous post but also introduces a lot of new concepts that are unique to glass and liquids. For the glass the layering of the texture is very similar to the box but instead of a bump layer we have a transparency layer (There is a bump in the material but it is a simple overlay which does not need a full layered texture.) Remember to keep in mind that black is 0 and white is 1 when working with the transparency and reflections. The label should not be transparent or reflective since we are going for a paper look, and the bottle should be transparent and reflective to give the look of glass. The fingerprints on the glass should be somewhere in the middle because they aren't completely see through or solid (Think of this as the blood from the last project.)

To get the glass to look more like glass there also needs to be some changes in the material itself. Big players in making this look right is the Index of Refraction being set to 1.52 (the value for glass, every existing material has a unique index of refraction.) And The BRDF being set to use Fresnel Reflections (this will pull information from the Index of Refraction.) Also once you get a glass that you like, save a preset, what's to stop you from using it again in the future when you need a place to start on some glass, it can only speed up your workflow, and it may come in handy later in this project too. Let's see how our bottle is looking so far.

I should probably note that I made the texture in photoshop as well as the bump, if you end up trying this, make it as outlandish and fun as you'd like. Now we have to fill it up, no fluids or anything like that, the liquid will just be another piece of geometry with some attribute changes. In fact you can just take that glass preset from earlier and change the "Color at Max Distance" value under the Advanced Refraction attribute and the index of refraction to 1.38.

Next is the caustics which is a special type of glow that certain materials give off when hit by light. Many sodas have this in the real world, so to make this look realistic we should add it too. This is done by creating a spot light that is in the same location as the key light, and in the mental ray section of the light attributes, checking the emit photons box and changing the photon intensity (Mine was 8000000, but it may very depending on the project, just know that this value will probably get really high.) Also while you work on caustics turn the bottle visibility off so it only effects the drink, and make sure you have some specific caustic render settings turned on. Once you get the results you want, turn off Rebuild Photon Map so it saves your desired result.

The finishing touch are the bubbles which are just polygon spheres with the soda material applied to them. I switched the Color at max Distance back from orange to white, but other than that, everything stayed the same. This is what I came up with. 

In the end it all comes together, looking at it again though, the caustics could be a bit darker to match the drink more, but I did learn a lot from this and now also have some valuable presets I can use in the future.