What is Ray Tracing? (Explained Simply)

by John Ruth

Put simply, ray tracing is a computer graphics technique used to imitate the way light works in real life. This is important for creating reflections, refractions, shadows and creating realistic lighting effects.

How it Works

  1. Casting Rays: Rays are cast from the viewer’s eye (camera) towards the 3D scene.
  2. Intersection Tests: Each ray checks if it intersects with any object in the scene.
  3. Color Calculation: If a ray hits an object, it calculates the color at the point of intersection, taking into account light sources, material properties, and other factors.
  4. Secondary Rays: Rays may spawn additional rays for reflections, refractions, or shadows.
  5. Recursive Nature: This process is often recursive, with secondary rays undergoing the same process as the primary rays.

Ray Tracing vs. Rasterization

Initially, GPUs were primarily optimized for a process known as rasterization, the backbone of real-time graphics rendering in video games and simulations. Rasterization is the traditional technique used in real-time graphics, which involves converting 3D objects into a 2D image quickly but with less realism.

With the advent of ray tracing, the demand for GPUs capable of handling more complex calculations has risen sharply.

Performance Trade-Off: Ray tracing is computationally more intensive than rasterization, leading to higher demands on processing power.

Role of GPUs in Ray Tracing

Modern GPUs have transcended their traditional roles, now coming equipped with dedicated cores specifically designed for ray tracing. These specialized GPU cores are engineered to handle the intensive computations required for tracing the path of light in a virtual environment, a task that involves complex mathematical calculations and extensive data processing.


A pioneer in this field, NVIDIA’s RTX series was among the first to introduce hardware-accelerated ray tracing. The RTX GPUs not only continue to handle traditional rasterization but also feature RT (Ray Tracing) cores that dramatically improve the efficiency and feasibility of real-time ray tracing in graphics-intensive applications.

AMD Radeon RX Series

Not far behind, AMD’s Radeon RX series also incorporates hardware support for ray tracing. By integrating these capabilities into their GPUs, AMD has ensured that a broader range of consumers and developers can access the power of ray tracing technology.

Software Support: The Backbone of Integration

The hardware advancements are just one side of the coin. To fully leverage the capabilities of ray tracing GPUs, robust software support is essential. APIs (Application Programming Interfaces) like DirectX Raytracing (DXR) and Vulkan Ray Tracing play a pivotal role in this ecosystem. They provide developers with the tools and frameworks necessary to integrate ray tracing into games and applications.

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