Stilia
Analysis
The section's first analysis: the two main ways to build an image of a 3D scene. In short, rasterization is fast and underpins real-time graphics, while ray tracing renders light more accurately and was long reserved for offline rendering, but is increasingly used in games too.
Basic facts
Rasterization converts a scene's triangles into screen pixels and then calculates the color of each pixel. This approach has been optimized in graphics processors for decades.
Ray tracing simulates the path of light rays: from the camera through each pixel into the scene and on to the light sources. Reflections, refractions and soft shadows arise naturally this way.
Since 2018, consumer graphics cards have offered hardware acceleration for ray tracing, and it has come to be combined with rasterization in real time.
Comparison criteria
| Criterion | Rasterization | Ray tracing |
|---|---|---|
| Speed | High, suitable for real time | Lower; in real time only with hardware acceleration and simplifications |
| Reflections and refractions | Approximations and special techniques | Arise naturally |
| Global illumination | Precomputation or approximations | Natural in the path tracing variant |
| Where it is used | Games, interfaces, interactive graphics | Film, visualization, and increasingly games |
Practical observations
Modern projects rarely use a single approach in pure form: rasterization builds the main image, while ray tracing adds reflections, shadows or lighting.
For an artist, it matters more to know which renderer a tool uses than to understand the differences between algorithms: material settings and the wait for results depend on it.
Limits of these conclusions
This analysis describes principles. Actual speed and quality depend on the implementation, the hardware and the scene, so we do not give comparative figures.
What is still unknown
- How soon path tracing will become standard in games without simplifications
- How neural image reconstruction methods will change rendering; these approaches are evolving quickly
Related sections
- HistoryA timeline of digital graphics, from Sketchpad to open-source Blender.
- Reading listsReading paths for beginners and for those who want to go deeper.
- ArticlesA map of topics and a catalog of upcoming publications.
Sources
- ACM SIGGRAPH educational materials
- GPU manufacturers' documentation on ray tracing
- Pharr, Jakob, Humphreys. Physically Based Rendering (open edition)
Information is current as of the date of preparation. If you spot an inaccuracy in dates or facts, check the primary sources listed below.