Transparent surfaces and glass

- [Instructor] When you work with architecture, you'll often need to do glass and other types of transparent surfaces. So let's take a look at how to do that. Now I have this scene here and as you can see, I've got some windows and then I also have this sphere here, which we'll use to kind of see some of these effects. Now I need to create a material that I'm going to turn into glass so I'm just going to select this sphere, right click, assign new material. Now, I'm going to use the Arnold Ai standard surface material. Now this will also work with the Maya standard surface material as well. So I'm going to go into the attribute editor, let's select this and let's just call this material glass. And then I also want to assign it to the windows so I'm going to go ahead and select just the windows, not the window frames. So I'm going to shift select all of these, right click, assign existing material glass. Okay, so I've got that material on all of these. So let's go ahead and set up an IPR so we can see how this all works. So I'm going to go ahead and select one of these objects and go into the attribute editor and highlight my glass material. Now, in order to do glass, your main controls are going to be under specular and transmission. Specular controls reflectivity, transmission controls how transparent that surface is. Now you can use the base color, but generally you don't want to use it because that's for solid color so I'm going to go ahead and turn my base weight all the way down, and then I'm going to turn my transmission all the way up and you can see that almost immediately, we're getting the effect that we want. Now, a lot of this is in transmission, but specular really controls kind of how the surface looks, because a lot of the surface that you are going to see is the reflections off of the surface and that's controlled by specularity. So the most important one here is roughness. If I turn roughness down, you'll see that this becomes a lot more transparent looking. Now you can see we're getting some reflections here, but if I turn up roughness all the way you see I'm getting almost like a frosted glass effect. So you want to keep that fairly low. Typically I keep it at .1 or below for normal type of glass but if you want to frost it a little bit more, you can certainly bring it up a little bit higher than that so I'm going to bring it around to about .05. And then in addition to this, we can have the weight of this so you can turn that down. So this will control how much reflection is seen. And then the other one is the IOR, in other words, that's called index of refraction and that kind of determines how this refracts light. So, glass is typically around 1.5, which is the default, but you can see in the sphere, as I turn this down, the index of refraction really changes the way this surface looks so when it's below zero, you're getting this kind of convex effect. And when you do it this way, you're getting more of a concave effect. So it's really the lens effect of that glass. Now, when it's at one, it's essentially transparent, you can barely see it, so this is really going to determine a lot how that surface is going to appear. Now, if you're doing a very specific material, you want to look up the index of refraction for that material and use that value. Otherwise, you're just going to have to basically use your eye to get the value that you want. Now, in addition to this, we also have transmission, which is kind of the heart of that surface, we can change the color. So if you want to, you can do for example, colored or tinted glass effects. So if I want this to be maybe a light blue or something like that, I can certainly do that. We can also do depth. Now the depth is how deep that color is going to be seen, so you can see that as I dial this up, that color goes closer and further away from the surface at zero, it's really not effective, but as you dial it in, you can start to see that. Now, in addition to this, we also have scattering, which kind of determines again, the frostiness of the glass. So once you have the depth turned up, that scattering kind of turns it up and you can also use this to create like fluid or water type effects as well. So as you can see, when you do transparency for glassy surfaces, your main controls are going to be under specularity and transmission.