✨ Special Material Types

Understanding Blend Modes

Before diving into specific material types, you need to understand Blend Modes—the fundamental setting that determines how a material interacts with whatever is behind it. This single property transforms how the entire material renders.

Find the Blend Mode in the Material Editor's Details panel under Material → Blend Mode. Let's explore each option:

Opaque (Default)

The standard mode for solid surfaces. Light doesn't pass through, and you can't see anything behind the object. This is the most performant option because the renderer doesn't need to composite multiple layers.

Use for: Walls, floors, rocks, metal, wood—any solid surface

Masked

Pixels are either fully visible or fully invisible based on an opacity mask. There's no partial transparency—each pixel is a hard yes or no. This enables complex shapes from simple geometry (a flat plane can display a detailed leaf).

Use for: Foliage, chain-link fences, grates, hair cards, decals with hard edges

Translucent

Allows partial transparency—pixels can be anywhere from 0% to 100% visible. This enables glass, liquids, smoke, and other see-through materials. However, it's more expensive to render than Opaque or Masked.

Use for: Glass, water, ice, smoke, holograms, UI elements in world space

Additive

Adds the material's color to whatever is behind it, making everything brighter. Black becomes invisible (adds nothing), while bright colors create intense glows. Cannot darken the scene.

Use for: Fire, magic effects, lens flares, energy beams, ghosts

Modulate

Multiplies the material's color with the background. White has no effect, black makes the background completely dark, and colors tint the background. Rarely used but useful for specific effects like shadows on transparent surfaces.

Use for: Projected shadows, colored glass shadows, special tinting effects

Figure: Each blend mode has distinct visual behavior and performance characteristics.

Translucent Materials

Translucent materials let you see through surfaces with varying degrees of transparency. They're essential for glass, water, ice, holograms, and any effect where background visibility matters.

Setting Up Basic Translucency

Step 1: Create a new material and open it in the Material Editor.

Step 2: In the Details panel, find Material → Blend Mode and change it from Opaque to Translucent.

Step 3: Notice that the Opacity input on the main material node is now active. This controls how see-through the surface is: 0 = fully transparent, 1 = fully opaque.

Step 4: Connect a value to Opacity. For simple glass, try a Constant with value 0.3 (mostly transparent).

Figure: A basic translucent glass material with tint, opacity, and low roughness.

Translucent Lighting Modes

Translucent materials have special lighting options found in Details → Translucency → Lighting Mode:

Volumetric NonDirectional: Cheapest option. Light affects the whole surface uniformly—no sense of direction. Good for particles and simple effects.

Volumetric Directional: Adds basic directional lighting response. The surface reacts to light direction but without full detail.

Volumetric PerVertex NonDirectional/Directional: Calculates lighting per vertex instead of per pixel. Faster but less accurate on detailed meshes.

Surface ForwardShading: Highest quality. Enables full PBR lighting including reflections and specular. Most expensive but looks best for glass and water.

Fresnel Effect for Realistic Glass

The Fresnel effect makes surfaces more reflective at glancing angles. Look at a window from straight on—you see through it clearly. Look at it from a sharp angle—it becomes mirror-like. This is Fresnel in action.

Add a Fresnel node to your material. Connect it to Opacity (inverted) so edges become more opaque, or use it to blend between reflection and transparency.

Figure: Fresnel makes glass more reflective at shallow viewing angles, mimicking real-world physics.

Refraction

Real glass bends light passing through it—this is refraction. Enable it in Details → Translucency → Refraction Mode (set to "Index of Refraction" or "Pixel Normal Offset").

The Refraction input on the material node controls the Index of Refraction (IOR). Common values:

• Air: 1.0 (no refraction)
• Water: 1.33
• Glass: 1.5
• Diamond: 2.4

Two-Sided Translucency

By default, materials only render on one side of a mesh (the side with outward-facing normals). For thin translucent objects like glass panes or bubbles, you often need both sides visible.

Enable Two Sided in the material's Details panel. For translucent materials, also consider enabling Two Sided Foliage if you want light to transmit through (useful for leaves and thin cloth).

Masked Materials

Masked materials create complex shapes from simple geometry using alpha textures. Unlike translucent materials, masked pixels are either fully visible or fully invisible—there's no partial transparency. This makes them more performant while still enabling detailed silhouettes.

Setting Up a Masked Material

Step 1: Create a new material. In Details, set Blend Mode to Masked.

Step 2: The Opacity Mask input becomes active on the material node. Connect a mask texture or value here.

Step 3: Adjust Opacity Mask Clip Value in the Details panel. Default is 0.333. Lower values show more of the mask; higher values cut away more.

Figure: Masked materials combine color textures with alpha masks to create complex shapes from simple geometry.

Common Masked Material Uses

Foliage: Leaves, grass, and plants use masked materials extensively. A simple card (two triangles) can display a detailed leaf shape.

Fences and Grates: Chain-link fences, ventilation grates, and railings use masks to show the gaps between solid parts.

Hair Cards: Character hair often uses textured planes with masked materials for individual strand detail without millions of polygons.

Decals: Many decals use masked materials for hard-edged shapes like logos, signs, and symbols.

The Clip Value Explained

The Opacity Mask Clip Value determines the threshold between visible and invisible. If your mask texture has a pixel with value 0.5:

• Clip Value 0.3 → 0.5 > 0.3 → Pixel is visible
• Clip Value 0.6 → 0.5 < 0.6 → Pixel is invisible

Adjusting the clip value lets you fine-tune the mask edge without changing the texture. Lower values reveal more; higher values cut more away.

flowchart LR
    subgraph Input["Mask Pixel Value"]
        P["Pixel: 0.5"]
    end
    
    subgraph Compare["Compare to Clip Value"]
        C1["Clip: 0.33\n0.5 > 0.33"]
        C2["Clip: 0.5\n0.5 = 0.5"]
        C3["Clip: 0.75\n0.5 < 0.75"]
    end
    
    subgraph Result["Result"]
        R1["✓ VISIBLE"]
        R2["Edge case\n(implementation varies)"]
        R3["✗ INVISIBLE"]
    end
    
    P --> C1 --> R1
    P --> C2 --> R2
    P --> C3 --> R3
    
    style R1 fill:#4CAF50,color:#fff
    style R2 fill:#ffc107,color:#333
    style R3 fill:#e74c3c,color:#fff
                

Figure: The Opacity Mask Clip Value determines the visibility threshold.

Two-Sided Foliage

For leaves and other thin masked surfaces, enable Two Sided so both sides render. Additionally, enable the Two Sided Foliage shading model if you want light to transmit through the surface—making leaves glow when backlit by the sun.

To use Two Sided Foliage shading:

Step 1: In Details, set Shading Model to Two Sided Foliage.

Step 2: A new input appears: Subsurface Color. This controls the color of light passing through. For leaves, use a warm yellow-green.

Masked vs Translucent: When to Choose

Figure: Choose Masked when possible for better performance; use Translucent only when gradual transparency is essential.

Emissive Materials (Glow Effects)

Emissive materials appear to glow—they emit light rather than just reflecting it. Neon signs, computer screens, magic effects, lava, bioluminescent creatures—all use emissive materials. The beauty is that emissive surfaces look bright even in dark environments, creating striking visual effects.

Basic Emissive Setup

Every material has an Emissive Color input on the main material node. Connect a color value here to make the surface glow. The material can still be Opaque—emissive works with any blend mode.

Step 1: Create a new material or open an existing one.

Step 2: Add a Vector Parameter for the glow color. Name it Emissive_Color. Set a vibrant color like bright cyan (0, 1, 1).

Step 3: Add a Scalar Parameter for intensity. Name it Emissive_Intensity. Set default to 5.0, with Slider Max around 50.

Step 4: Create a Multiply node. Connect the color to A and intensity to B.

Step 5: Connect the Multiply output to Emissive Color on the main material node.

Figure: Multiplying color by intensity allows easy control over glow brightness.

Understanding HDR and Bloom

Emissive values above 1.0 enter HDR (High Dynamic Range) territory. These super-bright values trigger the Bloom post-process effect, creating that characteristic glow halo around bright objects.

The relationship between intensity and visual result:

0.0 - 1.0: Normal brightness range. Visible but no bloom effect.

1.0 - 5.0: Bright with subtle bloom. Good for screens, indicator lights.

5.0 - 20.0: Strong glow with noticeable bloom halo. Neon signs, magic effects.

20.0+: Intense, almost blinding glow. Sun-like effects, explosions.

Emissive Textures

Instead of a solid color, you can use textures to control which parts of a surface glow. This is perfect for:

Control panels: Buttons and screens glow while the frame stays dark

Circuit patterns: Glowing lines on a dark surface

Lava cracks: Bright emissive in the cracks, dark rock elsewhere

Create or import a texture where bright areas represent glowing regions. Multiply this texture by your emissive color and intensity, then connect to Emissive Color.

Figure: An emissive mask texture controls which parts of a surface appear to glow.

Animated Emissives

Emissive materials become even more impactful when animated. Pulsing lights, flickering screens, energy flowing through circuits—all achieved by animating the emissive intensity or color over time.

Use the Time node combined with Sine to create smooth pulsing:

Time → Multiply (speed) → Sine → Remap/Abs → Multiply with color

The Sine node outputs values from -1 to 1. Use Abs (absolute value) for 0 to 1 range, or add 1 and divide by 2 for the same effect.

Emissive with Lumen

Unreal Engine 5's Lumen global illumination system can make emissive surfaces actually cast light onto nearby geometry. This creates incredibly realistic lighting from screens, signs, and glowing objects.

For Lumen to pick up emissive lighting, the emissive intensity generally needs to be quite high (50+). Adjust to taste while watching the light contribution in your scene. Lumen emissive lighting is fully dynamic—animate the emissive, and the light it casts updates in real-time.

Decals

Decals project materials onto other surfaces without modifying their geometry. Think of them like stickers for your 3D world—bullet holes on walls, dirt on floors, graffiti on buildings, blood splatters, footprints, and warning signs all use decals. They're incredibly versatile and performance-friendly.

How Decals Work

Decals use a Decal Actor that defines a projection volume (a box). Any surface geometry inside this box receives the decal material projected onto it. The decal follows the surface's shape, wrapping around corners and conforming to uneven terrain.

flowchart LR
    subgraph DecalActor["Decal Actor"]
        Box["Projection Box\n(defines area)"]
        Mat["Decal Material\n(what to project)"]
    end
    
    subgraph Scene["Scene Geometry"]
        Wall["Wall"]
        Floor["Floor"]
        Prop["Prop"]
    end
    
    subgraph Result["Result"]
        R1["Decal appears on\nall surfaces in box"]
        R2["Conforms to\nsurface shape"]
        R3["No mesh modification"]
    end
    
    Box --> Wall
    Box --> Floor
    Box --> Prop
    Mat --> R1
    Wall --> R2
    Floor --> R2
    Prop --> R2
    R2 --> R3
    
    style DecalActor fill:#667eea,color:#fff
    style Result fill:#4CAF50,color:#fff
                

Figure: Decals project their material onto any geometry within their volume.

Creating a Decal Material

Step 1: Create a new Material. In the Details panel, change Material Domain from Surface to Deferred Decal.

Step 2: Set the Blend Mode appropriately:

• Translucent: For decals with soft edges or partial transparency
• Masked: For decals with hard cutout edges

Step 3: Choose what the decal affects via Decal Blend Mode:

• Translucent: Affects Base Color, Metallic, Specular, Roughness, Normal, Emissive
• Stain: Only affects Base Color (good for dirt/stains that shouldn't change roughness)
• Normal: Only affects Normal (for adding surface detail without color change)
• Emissive: Only affects Emissive (for glowing decals like neon signs)

Step 4: Connect your textures to the appropriate outputs. Most decals need at least a Base Color (or Emissive) and an Opacity Mask.

Figure: Decal materials use Deferred Decal domain with appropriate blend modes.

Placing Decals in Your Level

Method 1 - Drag and Drop: Drag your Decal Material directly from Content Browser into the viewport. Unreal creates a Decal Actor automatically.

Method 2 - Decal Actor: Place → All Classes → search "Decal". Then assign your decal material in the Details panel.

Once placed, adjust the decal's transform:

• Position: Move the decal to where you want the effect
• Rotation: Rotate to face the surface (the decal projects along its local X axis)
• Scale: Resize the projection box—larger scale means the decal covers more area

In the Decal Actor's Details panel, adjust Decal Size for more precise control over the projection volume dimensions.

Decal Sorting and Priority

When multiple decals overlap, you need to control which one appears on top. Use the Sort Order property in the Decal Actor's Details panel. Higher values render on top of lower values.

For example:

• Base dirt layer: Sort Order 0
• Graffiti on wall: Sort Order 1
• Bullet hole on graffiti: Sort Order 2

Common Decal Uses

Environmental storytelling: Dirt buildup, water stains, rust, graffiti, posters, warning signs—all without modeling these details into every mesh.

Gameplay feedback: Bullet impacts, explosion scorch marks, blood splatters, footprints in snow. These are often spawned dynamically during gameplay.

Detail enhancement: Add normal-only decals to break up flat walls with cracks, scratches, or surface imperfections.

Signage and UI: In-world text, logos, and interface elements that need to appear on arbitrary surfaces.

Figure: Decals serve many purposes from environmental detail to dynamic gameplay effects.

Landscape Materials Introduction

Landscape materials are specialized materials designed for Unreal's Landscape system—the tool for creating large outdoor terrains. Unlike regular materials applied to static meshes, landscape materials need to handle multiple texture layers that blend based on painting, support massive scale with proper tiling, and maintain performance across potentially millions of polygons.

What Makes Landscape Materials Different

Standard materials apply uniformly across a mesh. Landscape materials instead define multiple layers (grass, dirt, rock, snow, etc.) that artists can paint directly onto the terrain in the editor.

Key differences from regular materials:

Layer-based: Multiple complete texture sets that blend together based on painted weight maps

Tiling considerations: Must tile seamlessly across enormous distances without obvious repetition

Performance critical: Landscapes can have millions of vertices—material complexity directly impacts frame rate

Painted blending: The Landscape tool paints layer weights; the material uses these weights to blend textures

flowchart TD
    subgraph Layers["Material Defines Layers"]
        L1["Layer 1: Grass\nGreen, low roughness"]
        L2["Layer 2: Dirt\nBrown, medium roughness"]
        L3["Layer 3: Rock\nGray, high roughness"]
    end
    
    subgraph Painting["Artist Paints Weights"]
        P1["Weight Map\n(per-layer masks)"]
    end
    
    subgraph Blend["Material Blends"]
        B1["Where weight = Grass\nshow grass textures"]
        B2["Where weight = Dirt\nshow dirt textures"]
        B3["Where weight = Rock\nshow rock textures"]
    end
    
    subgraph Result["Final Terrain"]
        R1["Seamless blended\nterrain surface"]
    end
    
    Layers --> Painting
    Painting --> Blend
    Blend --> Result
    
    style Layers fill:#4CAF50,color:#fff
    style Painting fill:#FF9800,color:#fff
    style Blend fill:#667eea,color:#fff
    style Result fill:#2196F3,color:#fff
                

Figure: Landscape materials blend multiple layers based on painted weight maps.

Landscape Layer Blend Node

The core of any landscape material is the Landscape Layer Blend node. This node takes multiple inputs (one per layer) and blends them based on the painted layer weights.

Each layer you add to the node requires:

Layer Name: A unique identifier like "Grass", "Dirt", "Rock"—this is what appears in the Landscape paint tool

Blend Type: How this layer blends with others

• LB Weight Blend: Standard painting—layers blend based on painted weight
• LB Alpha Blend: This layer paints over others completely (good for roads, paths)
• LB Height Blend: Uses height information for more natural blending at edges

Preview Weight: How much of this layer shows in the material preview (doesn't affect in-game)

Figure: The Landscape Layer Blend node combines multiple texture layers based on painted weights.

Height-Based Blending

Simple weight blending creates soft, uniform transitions between layers. For more natural results, use height-based blending. This technique uses a height map for each layer to determine which surface "wins" at blend boundaries.

For example, at a grass-rock boundary, instead of a smooth gradient, the rock texture appears where its height map is highest (representing raised rock surfaces), while grass fills the lower areas (representing soil between rocks). This creates much more realistic, organic-looking transitions.

Tiling and Macro Variation

Landscapes stretch across vast distances. A texture that tiles every 2 meters will repeat thousands of times across a terrain, creating obvious patterns visible from any distance.

Combat repetition with:

Large tiling values: Stretch textures further (but they may lose detail up close)

Distance-based tiling: Use different tiling for near vs. far viewing distances

Macro variation textures: Large-scale color variation overlays that break up patterns

Detail textures: High-frequency detail added up close that disappears at distance

When You'll Use Landscape Materials

You'll create landscape materials when working with:

• Outdoor open-world environments
• Terrain for any ground surface (natural or urban)
• Large-scale environmental art
• Games with paintable terrain (strategy games, builders)

We'll cover landscape material creation in full detail in the Landscape module, including practical exercises building multi-layer terrain materials with proper blending, tiling, and performance optimization.

Hands-On: Create a Glowing Emissive Material

Time to put your new skills into practice! In this exercise, you'll create a sci-fi control panel material with glowing elements that pulse over time. This combines emissive techniques with material parameters for maximum flexibility.

Part 1: Create the Base Material

Step 1: In Content Browser, create a new Material. Name it M_SciFi_Panel_Emissive.

Step 2: Double-click to open the Material Editor. This material will be Opaque (the default)—emissive works with any blend mode.

Step 3: Set up the base surface properties:

Create a Vector Parameter named Base_Color. Set Group to 01 - Surface. Default: dark gray (0.1, 0.1, 0.12). Connect to Base Color.

Create a Scalar Parameter named Roughness. Set Group to 01 - Surface. Default: 0.4, Slider Min: 0, Max: 1. Connect to Roughness.

Create a Scalar Parameter named Metallic. Set Group to 01 - Surface. Default: 0.8. Connect to Metallic.

Part 2: Add the Emissive Glow

Step 4: Create the emissive color parameter:

Add a Vector Parameter named Glow_Color. Set Group to 02 - Emissive. Default: bright cyan (0, 1, 1).

Step 5: Create the intensity control:

Add a Scalar Parameter named Glow_Intensity. Set Group to 02 - Emissive. Default: 10.0, Slider Min: 0, Slider Max: 50.

Step 6: Create a Multiply node. Connect Glow_Color to A and Glow_Intensity to B.

Step 7: Connect the Multiply output to Emissive Color on the main material node.

Step 8: Click Apply. You should see a solid glowing material in the preview sphere.

Figure: At this point, the material glows but doesn't animate.

Part 3: Add the Pulsing Animation

Step 9: Create the animation speed control:

Add a Scalar Parameter named Pulse_Speed. Set Group to 03 - Animation. Default: 2.0, Slider Min: 0.1, Slider Max: 10.

Step 10: Create the animation range control:

Add a Scalar Parameter named Pulse_Min. Set Group to 03 - Animation. Default: 0.3, Slider Min: 0, Max: 1. (This is how dim the glow gets at minimum.)

Step 11: Build the animation node chain:

Add a Time node (search "Time"). This outputs ever-increasing time in seconds.

Add a Multiply node. Connect Time to A and Pulse_Speed to B. This controls animation speed.

Add a Sine node. Connect the Multiply output to it. Sine converts linear time into smooth oscillation (-1 to 1).

Add an Abs node (absolute value). Connect the Sine output to it. This converts the range from (-1 to 1) to (0 to 1)—always positive.

Step 12: Remap the range to respect Pulse_Min:

Add a Lerp (Linear Interpolate) node. Connect Pulse_Min to A, connect a Constant of 1.0 to B, and connect the Abs output to Alpha.

This makes the pulse range from Pulse_Min (at minimum) to 1.0 (at maximum).

Step 13: Multiply this animation value into your emissive chain:

Add another Multiply node between your existing Glow_Color × Glow_Intensity multiply and the Emissive Color input. Connect the Lerp output to this new Multiply.

Your chain should now be: (Glow_Color × Glow_Intensity) × (Animated Pulse) → Emissive Color

Step 14: Click Apply. The preview should now show a pulsing glow!

Figure: The complete node setup with animation controls feeding into the emissive output.

Part 4: Create Material Instances

Step 15: Right-click M_SciFi_Panel_Emissive → Create Material Instance. Name it MI_Panel_Cyan_Fast.

Keep the defaults (cyan glow) but increase Pulse_Speed to 4.0 for a faster heartbeat effect.

Step 16: Create another instance: MI_Panel_Red_Alert. Configure:

• Glow_Color: Red (1, 0, 0)
• Glow_Intensity: 20 (brighter for alert)
• Pulse_Speed: 6.0 (urgent pulsing)
• Pulse_Min: 0.5 (doesn't get as dim)

Step 17: Create a third: MI_Panel_Green_Steady. Configure:

• Glow_Color: Green (0, 1, 0.3)
• Glow_Intensity: 8
• Pulse_Speed: 0.5 (very slow, calm)
• Pulse_Min: 0.8 (barely dims—almost steady)

Step 18: Place cubes or planes in your level and apply each instance. You now have three distinct panel styles from one parent material!

Bonus Challenge: Add an Emissive Mask

Want to take this further? Create or import a texture that defines which parts of a surface should glow (white areas glow, black areas don't). Multiply this mask into your emissive chain before the Emissive Color input. Now you can create control panels where only specific buttons and screens glow while the frame stays dark!

Summary

You've now mastered the special material types that bring variety and visual interest to your Unreal Engine projects. Let's recap the key concepts:

Choosing the Right Material Type

flowchart TD
    Start["What effect do you need?"] --> Q1{"See through\nthe surface?"}
    
    Q1 -->|No| Opaque["Use OPAQUE\n(best performance)"]
    Q1 -->|Yes| Q2{"Gradual or\nbinary transparency?"}
    
    Q2 -->|"Binary (on/off)"| Masked["Use MASKED\n(cutouts, foliage)"]
    Q2 -->|"Gradual (0-100%)"| Translucent["Use TRANSLUCENT\n(glass, water, smoke)"]
    
    Start --> Q3{"Need surface\nto glow?"}
    Q3 -->|Yes| Emissive["Add EMISSIVE COLOR\n(works with any blend mode)"]
    
    Start --> Q4{"Project onto\nother surfaces?"}
    Q4 -->|Yes| Decal["Use DECAL MATERIAL\n(Deferred Decal domain)"]
    
    Start --> Q5{"Terrain with\npainted layers?"}
    Q5 -->|Yes| Landscape["Use LANDSCAPE MATERIAL\n(Layer Blend nodes)"]
    
    style Opaque fill:#4CAF50,color:#fff
    style Masked fill:#8BC34A,color:#fff
    style Translucent fill:#FF9800,color:#fff
    style Emissive fill:#00BCD4,color:#fff
    style Decal fill:#9C27B0,color:#fff
    style Landscape fill:#795548,color:#fff
                

Figure: Decision tree for selecting the appropriate material type.

Performance Guidelines

Keep these performance principles in mind:

Prefer Opaque: Always start with Opaque. Only switch to Masked or Translucent when the effect truly requires it.

Masked over Translucent: If you don't need gradual transparency, Masked performs better and avoids sorting issues.

Limit translucent layers: Multiple overlapping translucent surfaces compound performance cost and can cause visual artifacts.

Emissive is cheap: Adding emissive to an existing material has minimal cost. The bloom post-process has its own cost but affects all emissives equally.

Decal efficiency: Keep projection volumes small. Use simpler Decal Blend Modes (Stain, Normal) when full Translucent isn't needed.

Landscape complexity: Limit layer counts. Each layer adds texture samples across millions of vertices.

What's Next?

Congratulations on completing the Materials and Textures module! You now have comprehensive knowledge of Unreal Engine's material system—from basic PBR principles through complex parameter systems to specialized material types.

In the next module, we'll explore Lighting—how to illuminate your scenes with different light types, build static and dynamic lighting setups, and create atmosphere with fog and post-processing effects. Your material knowledge will be essential as we learn how surfaces and lights interact to create compelling visuals.