Decals are a revolutionary feature in Unreal Engine that dramatically accelerate environment texturing. Discover how to use simple drag-and-drop assets, create complex custom decals in Photoshop, and master advanced techniques like animated caustics and flipbook motion graphics for cinematic results.
Unreal Engine (UE) continues to solidify its position as a powerhouse for film and Virtual Production, offering speed advantages that often surpass traditional DCCs like Blender or Maya, especially in environment detailing. The secret weapon for rapid cinematic texturing? Decals.
Decals are essentially textures projected onto any surface in the scene, acting as the ultimate tool for adding grime, damage, storytelling elements, and unifying disparate assets in a single, non-destructive step. Filmmaker and VFX artist Josh Toonen demonstrates exactly how these decal workflows can save artists hours while instantly lending a Hollywood look to their projects.
Instant Detail with Free Assets
For artists looking to instantly inject atmosphere into their environments, the first step involves leveraging UE’s extensive asset library. Josh highlights how users can tap into the Content Browser (Ctrl+Space) and the built-in Fab library to quickly filter for free Quixel Megascans assets.
These ready-to-use decals—ranging from grunge and cracks to bloody handprints—can be added to a project with a simple drag-and-drop action. This process is so fast that it fundamentally changes how artists approach Level Design and asset integration. The key manipulation involves aligning the decal using its blue projection arrow to ensure it hits the desired surface correctly. For layered complexity, artists can manage overlapping decals by adjusting their “sort order” in the Details panel, ensuring the newest or most important detail appears on top. For those eager to start experimenting, Josh offers a free Materials Starter Pack that includes caustics and gradient textures.
Creating Custom Decals in Photoshop
While the free library is extensive, custom effects often require bespoke decals. The journey begins in software like Photoshop where the central requirement is ensuring the image has proper transparency—the alpha channel. In Unreal Engine, white areas in the alpha are opaque, black is transparent, and gray allows for semi-translucency.
After exporting the finished graphic as a square PNG with transparency, the material creation process in Unreal requires specific settings:
1. Set the Material Domain to “Deferred Decal.”
2. Set the Blend Mode to “Translucent.”
The imported texture’s RGB channels connect to the Base Color, and its Alpha channel connects to the Opacity input. To sell the illusion of depth, Josh emphasizes the need for a Normal Map, which can be generated using external tools like SmartNormal. This simple addition allows bullet holes or cracks to catch the light realistically.
Advanced Decal Techniques
Decals aren’t just static stamps; they can be integrated deeply into Cinematic sequences and attached to moving objects.
Attaching Decals for Storytelling Effects
For dynamic effects, such as a lightsaber burn mark appearing on a character, the decal can be attached directly to the character mesh. By dragging the decal onto the character in the Outliner, artists can select a specific bone (like the spine or hand) for attachment. This guarantees the decal moves accurately with the character’s Motion Capture data.
Controlling when the decal appears is managed via the Sequencer. By keyframing the decal’s “Hidden in Game” property, artists gain precise control, switching visibility on and off exactly when the narrative requires.
Dynamic Motion via Material Panner
One of the most powerful advanced techniques involves creating animated effects like water caustics. This uses the material’s Panner node to manipulate the texture’s UV mapping over time. To achieve the complex, randomized motion seen in real caustics, two Panning setups are created with slightly different speeds and combined. The final result is then fed into the Emissive Color input of a Deferred Decal material, using a gradient texture to ensure soft, realistic edges and prevent hard lines.
Projecting Animated Motion Graphics
For the ultimate integration of Motion Graphics and live-action footage, artists can employ Flipbook materials. This technique involves compiling a sequence of animation frames (perhaps from After Effects or Nuke) into a single texture sheet, often an 8×8 grid containing 64 frames.
This texture is linked to a Flipbook material function that cycles through the frames. The magic lies in the Animation Phase input. Since this is exposed as a parameter, it can be keyframed directly within Sequencer. This gives the artist real-time, frame-accurate control over the projection of complex frame-by-frame animation, allowing for unprecedented cinematic control and flexibility.
Conclusion
Whether you are designing levels for a game or orchestrating a high-end cinematic, mastering decals is an essential skill for optimizing workflow and achieving high visual fidelity in Unreal Engine. Josh Toonen provides deeper dives into these techniques through his paid courses, including the 21 Day Unreal Filmmaking Bootcamp, but the foundational principles shared here are immediately applicable. Utilizing decals not only speeds up your texturing workflow but dramatically increases the storytelling potential of your projects.
To continue exploring high-impact techniques in UE, check out our resources on Environment & World Building or dive into advanced VFX & Simulation workflows.
