Join Craig Barr for an in-depth discussion in this video Material inputs, part of Unreal: Introduction to Materials.
- [Instructor] The material editor provides all of the tools and functions necessary to create some pretty fantastic materials for any project. There are several main inputs that really are the basic go-to inputs when creating an Unreal material. Let's explore and define these inputs here. So we're going to take a look at some of the basics around the material inputs for Unreal Engine materials. So, some of the basic inputs that we'll be working with here throughout this course are base color. This is the overall flat color of the material that you are working with.
So you can think of this as a flat diffuse color that you are using as your overall basic before any kind of effect or texture or anything else is happening to the surface of that material. Metallic. So, this is an interesting input, and we're going to cover this a little bit more when we get into physically-based materials, but for now, what metallic is is literally the level of metal-like that material might be. Zero, or towards zero being more non-metallic, zero being a completely non-metallic surface, and all the way up to one being a pure metallic surface.
So anything that was a pure metal, you'd be using metallic all the way up to a number one to give that surface a metallic feel. And with that, we have a couple of other inputs here. Specular and roughness. So first specular. This scales the specular for non-metallic surfaces. So what this means is that specular, for the most part, is an area you're going to use with non-metallic surfaces, so things that are towards the zero or are zero for an overall material in there. And this specularity will help you give that feeling that isn't overly shiny or reflective but has a little bit of specularity.
Everything in nature has some sort of specularity. There is nothing that is purely flat, so even non-metallic surfaces will have that loose specularity. And on that note, we get into roughness. Now, this is where roughness with metallic can really help define how metallic or shiny that substance is. So, this is where we define how rough the overall surface is, so something with zero roughness, for example, would be a very smooth surface, and something all the way up to a one would have a very rough level.
And what I mean by that is if you have a surface that is, for example, metallic and is disturbed or distorted on the surface by something like a displacement or a normal map, a roughness of one, you're really going to see that specularity reflection broken up across the surface. And it's also going to add to that overall metallic feel. Emissive. So emissive applies an overall glow effect to a material, so this can take a material of any kind, or even any node or input of a material, and turn it into a glowy substance or effect overall on the material.
Opacity, of course, controls the overall transparency of a material, and this works in the way of building transparent or even translucent materials, which we'll examine a little bit further on, as well as you could use opacity to drive an opacity mask for special effects like decals or separate logos as well. Normal. This addresses the ability to input a normal map, and a normal map is something where the surface is disturbed along the normal of the surface inputs on a material.
So, this is the, literally the input that's going to allow you to put in a normal texture map to provide that distortion or disturbance on the surface, so it really provides those details to that effect on a material. And the world position offset is a really interesting one. This is an area that you can actually animate to disturb the surface or disrupt the surface on a material, and you're animating this based on the material, not on the actual geometry or topology, but the material can effectively act as a vertex animator to disturb or offset things on the surface.
And we'll look at how we can work with those things as well. And ambient occlusion finally, this helps with inputting a map where you've calculated out self-shadowing or perhaps a cavity map as well. This really brings objects to life by kind of occluding the areas that light wouldn't maybe generally get to, so that everything isn't flat-lit. It really brings organic materials really to life as well. As we've seen in Unreal, the material editor allows us to have access to material inputs on the master material node.
This helps us beautify the surface of models overall and ultimately helps bring your Unreal project to life.
- Creating a simple material
- Applying materials to objects
- Editing materials
- Using textures with materials
- Creating PBR materials
- Adding effects such as transparency and animation