Allowing choice of surface types

- [Instructor] At this moment in time, we have more material slots than we do materials in our graph, and so let's put our metal material to good use and give our user the ability to switch between regular and premium versions or surface types for our product. With the product Y graph in view then, let's move the plastic material off to the left a little so as to give us some room to work which we will need as we have to add a few notes here to make this work. Let's then drag our metal material onto the graph and place it just underneath the plastic. We will also need to switch back to standard link creation mode for now if we haven't already, as we will need access to each of the individual material's output channels. With nothing selected, let's press the space bar key, and then search for and add a multi-switch node. The defaults of two and one for the input number and selection sliders will actually do nicely as we only have two choices of base materials that can be made. We will then want to pipe the base color of our plastic material into input one and the base color of the metal material into input two. After which, we will want to pipe the output of this node into the diffuse input of the first three materials on our blend node. Let's then copy the multi-switch node and do the same for the normal channel. So, place the plastic normal output into input one and the metal normal output into input two, making sure we pipe the multi-switch node into all three material normal inputs. Next up, we want to create a gray-scale multi-switch for the roughness channel. Apply both the plastic and metal roughness outputs to inputs one and two, and then pipe this into the appropriate slots on our multi-blend material. Now we want to finish off by copying this setup and doing the same for the metallic maps. Now that we have our two materials setup, we obviously won't want to force the user to have to swap between four different options just to be able to swap between both the standard and premium versions of the product. So, how can we make it so the client only needs to make a simple, one-click switch? Well, thankfully, Substance Designer actually makes this quite easy for us, in that, on the first of our multi-switch nodes, all we need to do it come to the parameters rollout, click on the function dropdown for the input selection, and after clicking on the expose option, select new from the dropdown list, and call this surface type. After which, we can click OK twice. What we can do now is expose this same parameter on all of the multi-switch nodes, only this time, choosing the option we just created, which will link all of the options to a single expose parameter. Let's make sure that it is clear to our user just what the option will change by clicking on the product Y package name. And then after scrolling down the parameters, open up the options for our newly created and exposed parameter. Let's copy the identifier into the label section, set the editor dropdown to dropdown list, and then add a second value, calling the first option plastic and the second metal. We will also need to renumber them as one and two, so that they work correctly. Once done, we can click the preview button to test our expose parameter. When we change the dropdown to metal now, this should affect every one of our four multi-switch nodes at the same time. And so, change the product over from plastic to metal. With our surface switch in place, time to give the user the important option of branding their product as they see fit.