Expose parameters

- [Narrator] So now we have our whole graph built, we're blending between different materials, we've set up all our outputs right and we've reviewed them. So in this chapter what we're going to do is we're going to do the work needed to prepare this, to then be able to bring it properly into Unreal as an SBSAR substance file. So the first thing we're going to do is we're going to look at how we can promote some parameters to have those visible in Unreal to be able to actually change parts of our substance within Unreal, and that's where a lot of the real power of this comes from, is building this generative procedural system, and being able to tweak it down the line in different content creation applications. So what I'm going to do, as we've been doing in all of these, is we're just going to bring our model back up into our viewer here, so you can see that. Okay, so obviously, almost any parameter can be promoted. And what I'm going to do to be able to show you the process and procedure of this in the most direct and obvious way, is we're going to promote the parameters of the colors of the two metals, so that in Unreal we could change those colors. 'Cause that would be a very striking difference and very obvious. You know, you can do a very complex array of things, and a lot of times, for example, creating parameters for more or less wear, or damage, or all these different sort of subtle things on an object. And I encourage you to go deep in exploring that, and then for this we're going to focus on sort of the most obvious kind of changes we could do to make this very clear. So what I'm going to do up here, is let's go to the gold area of our network, and I'm going to click on the lower, more saturated tile, that's the one that has sort of the organic noise in it. And what we're going to do here is we're going to go down to the metal color area under the advanced parameters, in the instance parameters area. And you can see, there's this little drop-down menu that has like a little sign wave on a graph here, and what we can do here is you can say, there's a few different options, but this last one that says expose. So we click on that, you can say select the name of the new input, I'm actually going to define a new name. I'm going to call this gold metal color, and say okay. And so now if I just click on the background of the graph, let me double click back there just to get on the base parameters of our whole substance graph, you can see under our input parameters, now there is this option here. And if I open up that menu, you can see that that gold metal color, you see it automatically put underscores in there, is now in there and that we have basically created a top-level parameter that will be then exposed when we publish this substance file. I'm going to change a few things here, I'm actually going to change the label to gold metal color, 'cause that will be the thing we actually see on the outside, and under the group I'm going to call it color. If we had a lot of parameters for different things, we could create all these groups so they would group nicely when the substance file was viewed in another application. That's it, that's all we need to do for that one, so there we go. Let me close this. Now let's do the same thing for the copper, so we can have both colors exposed within Unreal. So I'm going to click on my copper material here, again, under advanced parameters under metal color, I'm going to click on this drop-down menu and say expose. I am going to change its input name to new, and I'm going to call this copper metal color and say okay. Alright, again, if I double-click on the background, we go to our parameters for our whole graph, now you can see we have a second input parameter. Let me open that up, I'm going to change its label to copper metal color, under its group I'm going to change that to color again, and then you can see that it is represented in the top level of the UI here, where these are both in the color group, and we have called them a name. So there we go, now we've taken parameters within our substance and we've elevated those up to be exposed. So you can see that this is great too, you can see what we're getting out of this network, all the different output images, we aren't inputting any images into this, those are all going to be built into the graph, and we have our input parameters. Because of course, within our substance graph, there are countless numbers of variables and parameters. And everything, as with any of these systems, I work with Houdini a lot for example, and so often you build a very complex network, but you just want to have a few controls that are high-level to be able to control the larger swath of change without having to be super granular in everything. But any of these parameters in here, for example, we have a normal node here and you wanted the normal intensity to know just how much that bump would be, we could again, go over to here and we could expose that. So you can keep exposing as many parameters as you need to have the level of customization and flexibility you want to have in Unreal, or whatever other application you're going to use your substance file in. Okay, but now we've exposed those parameters, and now we're going to move on to looking at some of the other things we need to do to make sure our substance graph is going to work properly in Unreal.