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UE3 Home > Materials & Textures

Materials & Textures


Materials and the textures used within them determine the appearance of surfaces within the world. They control not only the color of the surfaces, but also how each surface interacts with light by applying a chosen lighting model and blending mode. The lighting model determines how the light interacts with the surface and the blending mode controls how the surface being rendered blends with the rest of the scene.


A Material is an asset which can be applied to a mesh to control the visual look of the scene. In general, when light from the scene hits the surface, the lighting model of the material is used to calculate how that light interacts with the surface. There are several different lighting models available within Unreal Engine 3's material system, but the Phong lighting model is use for what might be called "regular" lighting.

When the lighting calculation is being performed, several material properties are used to come up with the final color of the surface. These material properties are also called material inputs in the material editor and are things like DiffuseColor, EmissiveColor, SpecularColor, SpecularPower, etc.


The diffuse color of a material represents how much of the incoming light reflects equally in all directions. A value of (1,1,1) means that 100% of the incoming light reflects in all directions. Diffuse is not view dependent so it will look the same from any angle, but it does depend on the normal at each pixel. Diffuse color will only show up when affected by some un-shadowed lighting, because it scales the incoming lighting.


The emissive color of a material represents how much light the material emits, as if it were a light source, although it doesn't actually light up other surfaces in the scene. Since emissive is acting like a light source, it is not affected by lights or shadows. Emissive is sometimes used to represent the ambient lighting term.


Specular color represents how much of the incoming light reflects in a directional manner. The specular response is brightest when your eye lines up with the direction of the reflected incoming light, so specular is view dependent. The normal also affects specular because it affects the reflected light direction. Specular power controls how shiny or glossy the surface is. A very high specular power represents a mirror-like surface while a lower power represents a rougher surface.


Opacity controls how much light passes through the surface for translucent materials. This means a translucent surface acts like a filter on the scene that you see through it. A material with an opacity of 1 is fully opaque, while an opacity of 0 means it lets all light through.


The normal property represents the surface orientation. It can be specified per-pixel with the use of a normal map, and it has an effect on both diffuse and specular lighting.

Materials General Topics

Materials Content Creation Topics

Materials DirectX 11 Topics

Materials Tutorial Topics


Textures are images which are used in materials. They are mapped to the surfaces the material is applied to and either applied directly, i.e. for diffuse textures, or the values of the texels of the texture are used within the material as masks or for other calculations. In some instances, textures may also be used directly, outside of materials, such as for drawing to the HUD. For the most part, textures are created externally within an image editing application such as Photoshop and then imported into Unreal Editor through the Content Browser. However, some textures are generated within Unreal such as render textures. These generally take some information from the scene and render it to a texture to be used elsewhere.

A single material may make use of several textures that are all sampled and applied for different purposes. For instance, a simple material may have a diffuse texture, a specular texture, and a normal map. In addition, there may be a map for the emissive and specular power stored in the alpha channels of one or more of these textures.


You can see that, while these all share the same layout, the colors used are specific to the purpose of the texture.

Textures General Topics

Textures Content Creation Topics