Lighting & rendering · Intermediate
Ray tracing
Rendering by following rays of light for true reflections and shadows
What is ray tracing?
Ray tracing is a rendering method that follows rays of light as they bounce around a scene to work out what each pixel should show. Because it models how light really behaves, it gives natural reflections, soft shadows and refraction through glass, at a higher computing cost than rasterization.
Think of it like this
It is like working out a photo by tracing every line of sight from the camera back to the lights, one pixel at a time.
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 ray tracing works
- 01For each pixel, a ray is sent from the camera into the scene.
- 02When it hits a surface, new rays check lights, reflections and shadows.
- 03The results are combined into that pixel’s color.
- 04More rays per pixel mean less noise and a cleaner image.
Ray tracing vs rasterization
| Property | Ray tracing | Rasterization |
|---|---|---|
| How it works | Follows light rays | Projects triangles onto the screen |
| Reflections and shadows | Physically accurate | Approximated with tricks |
| Speed | Slower | Very fast |
| Typical use | Film, product shots, high-end games | Most real-time games and apps |
Rasterize when speed matters most; ray trace when lighting has to look true. Modern games often mix both.
Where ray tracing is used
- Product and architectural renders
- Film and animation frames
- Realistic reflections in modern games
Beginner tip
If a ray-traced render looks speckled, raise the sample count or turn on a denoiser before adding lights. Speckle usually means too few rays, not too little light.
Terms related to ray tracing
- Lighting & renderingPath tracingRay tracing that follows light through many bounces for photoreal images
- Lighting & renderingRasterizationThe fast way games and viewports draw 3D, by filling in triangles on screen
- Lighting & renderingGlobal illuminationLight that bounces between surfaces, filling shadows and carrying color
- Lighting & renderingCausticsBright patterns of light focused by glass, water or polished metal
- Lighting & renderingRenderingTurning a 3D scene into finished images or video frames
- Lighting & renderingDenoisingCleaning the grainy speckle out of a fast render
Ray tracing FAQ
Updated October 29, 2026 · Browse all 3D terms