Reflections

Checked with version: 5.1

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Difficulty: Beginner

Reflection Source

By default, objects in a scene are rendered using Unity’s ‘Standard Shader’. The Standard Shader is a 'physically based shader' (PBS). This attempts to accurately represent the behavior of light on materials by mimicking physical properties such as reflectivity and the principles of ‘energy conservation’ which exist in the real world.

When using the Standard Shader, every material has a degree of reflectivity based on its ‘specularity’, or ‘metalness’. Without hardware powerful enough to ray trace reflections in realtime we have to rely on pre-rendering reflections. We do this with a cubemap - a 6-sided image of the world derived either from the sky, or from a ‘Reflection Probe’ which renders the environment from a specific point in space, writing the results to a texture. This is then blended with other lighting and surface data by a material’s shader in order to approximate the effects of reflectivity, like we see in the real world.

Reflection Source By default, highly Specular/Metal materials in your scene will reflect the Skybox, defined by the Reflection Source property of the Environment Lighting Panel. This behaviour can be changed by choosing a different source, or by adding a Reflection Probe to your scene.

By default, objects in a Unity scene will reflect the Skybox. However, this behaviour can be changed globally in the Lighting window using the ‘Reflection Source’ property. The Skybox, or alternatively, a custom cubemap may be used. This ‘Reflection Source’ can be thought of as a scene-wide cubemap used by all objects in the scene, unless overridden - by adding a Reflection Probe.

Reflection Probes

Often it is undesirable for objects to simply reflect the Skybox in a Unity scene. In many instances, objects may be blocked or ‘occluded’ from the sky. They may be indoors or underneath an architectural feature like a bridge or tunnel . To create more accurate reflections we need to sample what objects ‘see’ using a ‘Reflection Probe’. These probes render the world from their position in 3D space and write the results to a cubemap. This can then be used by nearby objects to give the impression that they are reflecting the world around them.

A reflection probe can be added via (GameObject>Light>Reflection Probe).

The position of a Reflection Probe will determine what the generated cubemap looks like, and therefore what is ‘seen’ in the reflections. Generally, for performance reasons it is better to use as few probes as possible. Remember, reflection probes are not meant to give physically accurate results, but instead give the impression of reflections in the game world. A few well placed probes throughout your scene will be sufficient in most cases.

Reflection Probes Left: Our scene with default reflections. Right: With a Reflection Probe added.

In the Inspector panel for a Reflection Probe we can set the ‘Type’ property of the probe to choose between ‘Baked’, ‘Custom’ or ‘Realtime’. It should be noted that Realtime Reflection Probes are extremely detrimental to performance as we are effectively rendering the scene an additional 6 times for each probe. There are specific cases where a realtime reflection probe is required and this expense is justified, but as a general rule, Baked Reflection Probes are preferable as they are considerably more performant.

Note that GameObjects are only visible to Baked Reflection Probes if marked as ‘Reflection Probe Static’ from the ‘Static’ drop-down at the top of the Inspector panel. Conversely, ‘Realtime’ probes render all visible GameObjects in the world unless a culling mask is applied.

Graphics

  1. Introduction to Lighting and Rendering
  2. Choosing a Lighting Technique
  3. The Precompute Process
  4. Choosing a Rendering Path
  5. Choosing a Color Space
  6. High Dynamic Range (HDR)
  7. Reflections
  8. Ambient Lighting
  9. Light Types
  10. Emissive Materials
  11. Light Probes
  1. Introduction to Precomputed Realtime GI
  2. Realtime Resolution
  3. Understanding Charts
  4. Starting the precompute process
  5. Probe lighting
  6. Unwrapping and Chart reduction
  7. Optimizing Unity's auto unwrapping
  8. Understanding Clusters
  9. Fine tuning with Lightmap Parameters
  10. Summary - Precomputed Realtime GI
  1. Lighting Overview
  2. Lights
  3. Materials
  4. The Standard Shader
  5. Textures
  6. Using Skyboxes
  7. A Gentle Introduction to Shaders
  8. Using detail textures for extra realism close-up
  9. Frame Debugger
  1. Cameras
  2. Image Effects: Overview
  1. Meshes
  2. Mesh Renderers and Mesh Filters
  1. Where to Start?
  2. Preparing Unity Render Settings
  3. Lighting Strategy
  4. Modeling
  5. Standard Shader/Material PBS and texturing
  6. Lighting and Setup
  7. Understanding Post Process Features
  8. Dynamically Lit Objects
  9. Sample Project File
  1. Using Cameras
  2. Using Lights
  3. Fun with Lasers!
  4. The Particle System
  5. Cinematic Explosions - PIT
  6. Cinematic Composition - PIT
  7. Image Effects: Overview
  8. Fun with Explosions!
  9. Exploring the Blacksmith Environment
  1. Turning it up to 11: Making Unity 5 look Awesome!
  1. Substance - Introduction
  2. Substance - Understanding PBR
  3. Substance - Working with PBR in Unity
  4. Substance - Using Substance materials in Unity
  5. Substance - Optimization for Substance materials
  6. Substance - Creating rock shapes
  7. Substance - Creating rock material, Pt 1
  8. Substance - Creating rock material, Pt 2
  9. Substance - Creating the dirt ground material
  10. Substance - Creating the rock ground material, Pt 1
  11. Substance - Creating the rock ground material, Pt 2
  12. Substance - Publishing the Substance
  13. Substance - Creating a blocking scene
  14. Substance - Creating the ground model
  15. Substance - Modelling the rock assets
  16. Substance - Texturing the upper body
  17. Substance - Exporting textures from Substance Painter
  18. Substance - Creating a scene in Unity, Pt 1
  19. Substance - Creating a scene in Unity, Pt 2
  1. Introduction and Goals
  2. Flame Particles Overview
  3. Particle Emission and Color
  4. Adding Movement To Particles With Noise
  5. Creating The Ember Particles
  6. Adding Lighting To Particles
  7. Creating Sparks With Particle Trails
  8. Particle Question and Answers
  1. Introduction and Goals
  2. Adding a Second Camera
  3. Adding Minimap Icons
  4. Render Textures and UI
  5. Adding A UI Mask and Border Image
  6. Questions and Answers
  1. Session Introduction
  2. Rendering In Unity
  3. Anatomy Of An Unlit Shader
  4. The Vertex Function
  5. The Fragment Function and Color Tint
  6. Making A Transparent Shader
  7. Displacing Vertices and Clipping Pixels
  8. Questions and Answers
  1. Introduction and Session Goals
  2. The VideoPlayer Component
  3. Texturing Objects With Video
  4. Playing and Pausing
  5. Playing A New Clip
  6. Displaying Current Time and Clip
  7. Animated Playhead
  8. Questions and Answers
  1. Overview and Goals
  2. Tonemapping and Color Grading
  3. Camera Movement & Animation
  4. Post Processing Volumes
  5. Timeline & Cinemachine
  6. Questions and Answers