Unity Lighting Techniques: Achieving Realistic Lighting

February 25, 2025

Is your Unity game’s lighting flat and lifeless? Learn how to harness the power of realistic lighting and transform your game’s visuals. This article explores techniques to achieve realistic lighting, providing practical guidance for developers to improve their games’ visual fidelity. If you’re looking to speed up your game development process, consider using Wayline, a comprehensive platform with tools and resources at every stage.

Overview of Unity’s Lighting System

Realtime lighting is calculated every frame, offering dynamic interaction but demanding processing power. Baked lighting pre-calculates lighting data and stores it in lightmaps for static objects, boosting performance. Consider the performance implications. Think about the desired level of interactivity when choosing between realtime and baked lighting.

Need dynamic lighting but want to save on performance? Mixed lighting combines realtime and baked elements. For optimal performance, bake as much as possible and use Realtime lights sparingly.

Directional Lights simulate distant light sources like the sun, ideal for outdoor scenes.

Photograph of a sun-drenched forest with dappled light filtering through the leaves, showcasing the effect of directional lighting

Point Lights emit light from a single point, useful for lamps and localized effects.

Photograph of a dimly lit cave with a single point light source illuminating a small area, highlighting the use of point lights for localized effects

Spot Lights emit light in a cone, perfect for creating dramatic spotlight effects or simulating car headlights.

Photograph of a stage with a single spotlight shining on a performer, demonstrating the dramatic effect of spot lights

Area Lights (Baked Only) simulate light from a surface, ideal for achieving soft, realistic lighting from windows or light panels.

Light Components consist of Intensity (brightness), Color, Shadows (enable and configure shadow casting), and Cookies (textures to shape the light’s appearance).

Global Illumination (GI) in Unity

Global Illumination (GI) simulates how light bounces off surfaces, creating realistic scenes.

Photograph of a serene mountain valley at sunset, exemplifying the impact of global illumination on the environment

GI calculates indirect lighting by simulating light bounces. This creates a more realistic and immersive visual experience.

Baking GI can dramatically improve performance. Enable Baked GI in the Lighting window (Window > Rendering > Lighting). Adjust settings like Indirect Resolution and Bake Resolution to balance quality and baking time, then click “Generate Lighting” to bake.

Enable Realtime GI in the Lighting window and adjust settings like Indirect Resolution and CPU Usage. Realtime GI is performance-intensive, so use it mindfully.

Lightmapping generates textures that store baked lighting. Optimize lightmaps by adjusting the Texel Size in the Lighting window, using multiple lightmaps for large scenes, and enabling compression to reduce memory use.

Light Probes allow dynamic objects to receive indirect lighting. Create Light Probe Groups around your scene and ensure dynamic objects have “Receive Global Illumination” set to “Light Probes.”

Working with Physically Based Rendering (PBR) Materials

Physically Based Rendering (PBR) simulates how light interacts with materials realistically.

Photograph of a close-up of a weathered stone wall, demonstrating the realistic surface details achieved through PBR materials.

PBR materials use properties based on real-world physics, creating consistent lighting across different environments.

Albedo provides the base color. Normal maps simulate intricate surface details. Metallic values define how reflective the surface is. Roughness determines how diffuse the reflections are. Ambient Occlusion simulates contact shadows.

Create PBR textures using software like Substance Painter or download them. Import these textures into Unity and assign them to the appropriate material slots. If you need some ready-made PBR materials, consider browsing Strafekit for high-quality assets.

Experiment with Metallic and Roughness values to achieve the desired material look. Higher Metallic and lower Roughness create a shiny, metallic surface. Lower Metallic and higher Roughness create a matte, diffuse surface. Reference real-world images when calibrating PBR materials. Doing so helps ensure your materials look grounded and believable, as they reflect real-world lighting conditions. Your eyes are your best tool here.

Shadows: Achieving Realistic Shadow Quality

Unrealistic shadows can ruin immersion faster than bad dialogue. Here’s how to get shadows right in Unity.

Hard Shadows have sharp edges, while Soft Shadows have blurry edges. Choose the right shadow type for the desired effect.

Increase shadow resolution for sharper shadows and adjust the shadow distance to control how far shadows render.

Shadow Cascades (Directional Lights) use multiple shadow maps to maintain quality at different distances.

Adjust Shadow Bias and Normal Bias to reduce shadow artifacts.

Experiment with shadow settings and light angles to minimize those pesky shadow artifacts. If you are having trouble with shadow artifacts, consider applying the Buto visual effect.

Post-Processing Effects for Enhanced Lighting

Post-processing can elevate your lighting and add depth that makes scenes feel more realistic.

Ambient Occlusion (SSAO) simulates subtle contact shadows, grounding objects and adding a sense of depth.

Bloom creates a glowing effect, simulating how bright light overpowers a camera sensor.

Color Grading adjusts the overall color and tone, allowing you to set the mood and atmosphere of your game.

Tone Mapping converts high dynamic range (HDR) to low dynamic range (LDR) for display.

Anti-aliasing reduces jagged edges.

Depth of Field simulates camera focus and blur.

Balance subtle effects like Ambient Occlusion with bolder effects like Bloom to create a unique visual signature for your game.

Optimizing Lighting for Performance

Optimizing lighting is essential for smooth performance. If you’re looking to optimize your game even further, check out our Unity Mobile Game Optimization Checklist.

Minimize the number of realtime lights; they are performance-intensive.

Bake lighting for static objects to lightmaps.

Place light probes strategically for accurate indirect lighting.

Reduce shadow resolution and distance for less important lights.

Use LOD groups for static meshes to reduce polygon count.

Advanced Lighting Techniques

Ready to take your lighting to the next level? Explore these advanced techniques for truly stunning visuals.

Use textures (light cookies) to shape a light’s appearance. This can be particularly useful for creating realistic window or foliage shadows.

Write custom shaders to achieve specific effects. Tailor lighting models to create stylized visuals or mimic unique material properties. If you’re looking to create custom shaders without code, check out Unity Shader Graph: Creating Custom Shaders Without Code.

Add depth with volumetric lighting and fog. Experiment with different fog densities and colors to create a sense of mystery or dread.

Implement screen space reflections (SSR) for realistic reflections. SSR approximates reflections by using the rendered screen data.

Utilize ray tracing (if hardware allows) for extremely realistic results. Ray tracing simulates the path of light rays for more accurate and physically plausible lighting.