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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.

Material

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.

Diffuse

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.

Emissive

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

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

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.

Normal

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

Material Editor User Guide - Overview of the node-based Material Editor in UE3.
Material Instance Editor User Guide - Overview of the editor for Material Instances in UE3.
Materials Overview - Descriptions of Material inputs and properties.
Instanced Materials - Overview of the material instancing system in UE3.
Material Instance Constant - Guide to using parameterized materials instances.
Material Instance Time Varying - Guide to using time-varying material instances.
Lit Translucency - Overview of using statically-lit translucency.
Mobile Material Reference - Information about creating materials for mobile devices.

Materials Content Creation Topics

Materials Tutorial - Guide to creating simple materials.
Materials Compendium - Descriptions of all expressions nodes available in the materials system.
Material Examples - Tips, tricks, and techniques for creating different types of materials.
Material Basics - Introduction to basic materials.

Material Functions - Explanation of material functions.

Custom Lighting - How to use the custom lighting model.
Anisotropic Lighting - How to use the anisotropic lighting model.
Soft Masked - Overview of the soft-masked blending mode.
DepthBiasBlend Usage - Guide to using the DepthBiasBlend expression.
Creating Hair Using Alpha - Creating hair using materials and meshes in UE3.
Fake Mesh Lighting - How to fake lighting on meshes and particles using materials.
World Position Offset - How to use the WorldPositionOffset material input.
Material Masks - Creating masks and gradients algorithmically using material expressions.

Materials DirectX 11 Topics

Image Based Reflections - Rendering whole-scene, HDR reflections.
Screen Space Subsurface Scattering - SSS material effect for realistic human skin.
Tessellation - Generate more triangles from a mesh for smoother surfaces including silhouettes.

Materials Tutorial Topics

Creating Distorted Reflections - How to create materials that reflect the scene.
Dynamic Normal Maps - Generating a normal map from a height map within a material.
Parallax Occluded Mapping - Adding parallax occlusion to a material.
Rendering Occluded Actors - Rendering "ghosts" of actors hidden behind geometry.
Real Time Deformation - How to create a surface which can be deformed at real time.
HUD Distortion - How to create a HUD distortion post process effect.

Textures

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

Texture Support And Settings - Information on engine and hardware texture support.
Texture Properties - Descriptions of the various properties for textures in UE3.
Normal Map Formats - Overview of the different types of compression applied to normal maps.
Flipbook Textures - Overview of 'flipbook' animated textures in UE3.
Movie Texture - Overview of the integrated movie texture system.
Render To Texture - Overview of the render=to-texture system in UE3.
Mobile Texture Reference - Information dealing with textures on mobile devices
Texture Streaming - Overview of the texture streaming system in UE3.

Textures Content Creation Topics

Creating Textures - Tips for creating textures for use with normal mapped materials.
Importing Texture Tutorial - How to get textures into Unreal Engine 3.
Creating Normal Maps - Practical advice and resources for creating normal maps.
Creating Shade Maps - Guide on creating shade maps using 3dsMax.
Importing Fonts - How to import true type fonts for use in UE3.
Taking Better Photos For Textures - Tips on taking photos for use as texture references.
Texture Optimization Techniques - Methods of reducing the amount of memory taken up by textures.