Lighting & rendering · Intermediate
Screen-space reflection
A real-time trick that builds reflections from what is already on screen
Also called SSR
What is screen-space reflection?
Screen-space reflection, or SSR, is a real-time trick that builds reflections from the image already drawn on screen. It reuses those pixels to show reflections on floors, water and glossy surfaces cheaply, but it cannot reflect anything the camera cannot currently see.
Think of it like this
It is like painting a puddle’s reflection using only what is in your photo. Anything outside the frame or hidden behind objects cannot appear in it.
Where it fits in a 3D project
- Create
- Surface
- Rig
- Animate
- Render
- Export
Render: Lighting the scene and turning it into images or video.
How screen-space reflection works
- 01The engine draws the scene and keeps its color and depth images.
- 02For each shiny pixel, it steps a ray across the screen image.
- 03Where the ray meets something in the depth image, that pixel’s color is borrowed.
- 04If the ray leaves the screen, a fallback such as a prebaked environment image fills in.
Screen-space reflection vs ray-traced reflections
| Property | Screen-space reflection | Ray-traced reflections |
|---|---|---|
| Source | Pixels already on screen | The full 3D scene |
| Off-screen objects | Missing | Reflected |
| Cost | Low | High |
| Typical flaws | Fading edges and gaps | Noise at low samples |
Use SSR as the cheap default for floors and water, and ray-traced reflections when mirrors, cars or glass must show what is behind the camera.
Where screen-space reflection is used
- Wet streets and puddles in games
- Polished floors in real-time architecture tours
- Water surfaces in interactive scenes
Beginner tip
SSR works best on surfaces facing up, like floors, seen at an angle. Vertical mirrors mostly reflect what is behind the camera, so plan a different method for them.
Terms related to screen-space reflection
- Lighting & renderingSpecular reflectionMirror-like reflection that creates shiny highlights on a surface
- Lighting & renderingRay tracingRendering by following rays of light for true reflections and shadows
- Lighting & renderingReal-time renderingDrawing 3D images fast enough to react instantly, as in games and viewports
- Lighting & renderingRasterizationThe fast way games and viewports draw 3D, by filling in triangles on screen
- Lighting & renderingFresnel effectWhy surfaces turn more mirror-like when you view them at a glancing angle
Screen-space reflection FAQ
Updated October 29, 2026 · Browse all 3D terms