Ray Tracing vs. Path-Tracing: What’s the Difference?

Ray Tracing vs. Path-Tracing infographic

Ray Tracing vs. Path-Tracing: What’s the Difference?

Ray tracing and path tracing are two technologies used in video gaming and filmmaking to create realistic scenes. They share some similarities, such as the formula they use to mimic light behavior and the fact that their GPUs use similar units to speed up the process. However, they also have several key differences. Most people can’t tell the difference between ray tracing and path tracing, but hopefully, this explanation will clear things up for you!

Path tracing is a Monte Carlo technique used in computer graphics to produce three-dimensional scenes with accurate global illumination. The approach involves integrating all of the illuminations reaching a single spot on an object’s surface.

Ray tracing is an advanced and realistic method of creating light and shadows in a scene. It is a technique that mimics how light in video games behaves in the real world. It uses an algorithm to trace the route a beam of light would take in the physical world. This method allows game developers to simulate virtual light beams that appear to reflect off objects, cast believable shadows, and produce realistic reflections.

This blog will look at the differences, pros, and cons between ray tracing and path tracing to help you identify which is the best.

Ray Tracing vs. Path Tracing: A Side-by-Side Comparison

Ray Tracing Path Tracing 
What is it?An advanced and realistic method of creating light and shadows in a scene that creates more realistic scenesA Monte Carlo technique used in computer graphics to produce three-dimensional scenes with accurate global illumination, improving the quality of videos and pictures
Games that Use the Technology 250N/A
Invented byAlbrecht DürerJames Kajiya
How it WorksIt sends single-ray pixels at a time that mimics genuine light rays and traces the path that a beam of light would travel in the real environment using an algorithmIt sends tens, hundreds, or thousands of pixels at a time, and when they hit the surface randomly, there is a better quality of images and videos

Ray Tracing vs. Path Tracing: 4 Must-Know Facts

  1. In ray tracing, each ray is tracked back to one or more light sources by computing its precise path of reflection or refraction.
  2. Path tracing generates several rays for each pixel, but they bounce off in arbitrary directions.
  3. Ray tracing shoots one ray from each pixel. Path tracing doesn’t send one ray but tens, hundreds, or thousands of each pixel rendered. So, when you increase the samples per pixel, you can see that the quality improves.
  4. Ray tracing creates realistic shadows, especially in dark and bright scenes, giving the scene great definition. Path tracing is more advanced when it comes to creating images and lighting. 

Ray Tracing: Complete History

Ray tracing has been around for a while, dating back to the 16th century when the German painter, Albrecht Dürer, had an idea. He described a device known as a Dürer’s door that draws an object’s contours by having a thread attached to the end of a stylus that a helper drags along. The thread travels through the door’s frame before passing through a wall hook. In ray tracing, the hook serves as the center of projection, representing the camera position, and the thread creates a ray.

Then, in 1968, Arthur Appel decided to create shaded images using ray tracing on a computer. Using primary visibility, Appel utilized ray tracing to establish the nearest surface to the camera at each picture point. To determine whether a point was in shadow or not, he followed secondary rays from each shaded point to the light source.

Come 1971 and Goldstein and Nagel decided to publish 3-D visual stimulation where the reverse simulation of the photographic process via ray tracing is used to create shaded images of solids. In 1976, Scott Roth used ray casting to create a flip book animation for Bob Sproull’s computer graphics course at Caltech. 

Turner Whitted was the first to use recursive ray tracing for mirror reflection successfully. Additionally, he observed refraction through transparent objects using an angle dependent on the object’s index of refraction. He was the first to employ ray tracing for anti-aliasing and he also showed ray-trace shadows. As an engineer at Bell Labs, he created a recursive ray-traced movie in 1979 called The Compleat Angle.

Ray tracing has been improved over the decades, as most computer-generated imagery was only using additional lights. But, physical-based light transport was made possible by ray tracing-based rendering.

Light refraction ray tracing
Ray tracing employs light refraction to trace light paths.

Ray Tracing vs. Path Tracing: What’s the Difference?

In summary, both algorithms are meant to create realistic images by tracing light paths; however, they go about it in different ways. Here are some of the key differences between the two:

  • Ray tracing projects rays in all directions from numerous places. In path tracing, the physics of light is stimulated by incorporating ray tracing as part of a more extensive light stimulation system.
  • Ray tracing is a technique for generating an image by tracing the path of light as it bounces off objects. Path tracing is a similar technique, but it traces the path of light through a scene by following individual light rays.
  • Ray tracing can produce more realistic images than path tracing, but it is also more computationally expensive. For example, ray tracing can produce realistic images of reflections and refractions, while path tracing cannot.
  • Path tracing is more accurate than ray tracing when it comes to simulating the physics of light.
  • Path tracing can handle complex scenes with many objects more efficiently than ray tracing.
  • Ray tracing is more efficient at handling reflection, while path tracing is more efficient at handling refraction.
  • Path tracing typically produces noisier images than ray tracing, but the noise can be reduced by increasing the number of samples per pixel.

Both ray tracing and path tracing are powerful tools for generating realistic images. However, each approach has its own strengths and weaknesses. Ray tracing is more efficient at handling reflection, while path tracing is more effective at handling refraction.

Pros and Cons of Ray Tracing and Path Tracing

Both path tracing and ray tracing are rendering algorithms for generating realistic images. Both algorithms create images by tracing the path of light through a 3D scene, but they use different methods to determine the path of light.

Path tracing is known to send multiple pixels, improving the quality of images and videos. Ray tracing can send more limited paths, resulting in lower-quality images and videos. However, each has its benefits and drawbacks.

Below let’s look at the pros and cons of ray and path tracing.

Pros of Ray TracingCons of Ray Tracing
It features amazing, realistic aesthetics. The difference between the game and reality will be narrower than ever. As a result, it offers some of the most exquisite vistas and computer-generated graphics you have ever seen.It is expensive to purchase graphics cards that have access to ray tracing
Ray tracing is a feature that top-tier graphics cards have access to, and regardless of whether you enable it or not, you’ll get an incredible gaming experienceYou might have to play some games on lower settings to retain a consistent experience while activating the ray tracing option. This is because it takes significant processing resources to render the technology.
If you have access to ray tracing, you will receive the best visual experience possible for every game you purchase.In competitive scenarios, ray tracing’s hardware requirements can frequently hinder gameplay
It gives you photorealistic results.Ray tracing still needs a lot of processing power
It shoots a single pixel
Pros of Path TracingCons of Path Tracing
Path tracing uses integral equations to model light transport inside a scene and can be used to resolve more complicated lighting situations by resolving an integral equation that models light propagation inside the environment. It symbolizes a more systematic method of creating images that can accurately reproduce a wider variety of light or surface interactions.It is slower with displacement.
It shoots multiple pixels, ranging from tens to thousands, in random directions, improving the quality of images and videos.It needs more samples to produce a smooth motion blur and depth of field.
It effectively renders dense scenes and densely tessellated geometries (crowds, forests, etc.). 
Massive instancing makes it possible to render crowds, trees, buildings, and other redundant scene objects with minimal memory usage.
It supports Multi-Light output.
It supports geometrical camera projections.

Ray Tracing vs. Path Tracing: Which is Better? 

Our top choice is path tracing when comparing it to ray tracing, most simply because ray tracing shoots one ray from each pixel. A video with fewer pixels has a lower resolution, whereas one with more pixels has a higher resolution. Thus, ray tracing video content may be affected by the number of pixels sent at a particular time. 

Path tracing sends tens, hundreds, and thousands of rays for each pixel to be rendered. When the rays hit the surface, it doesn’t trace a path to every light source. It bounces the ray off the surface and then keeps bouncing unit it hits a light source. 

It also consumes a significant amount of computational power. If you don’t fire enough rays per pixel or don’t go down the paths thoroughly enough, you’ll get a splotchy image. That is because many pixels cannot locate light sources from their rays. As a result, you can see how the image quality improves as the number of samples per pixel increases.


Frequently Asked Questions

What does path tracing do?

Path tracing is a method that sends rays from the camera and repeats the procedure until a ray reaches a light source after hitting a reflective or refractive surface. A “path” is formed by the series of rays that travel from the camera to the light.





Is ray tracing accurate?

The best use of ray tracing is for rendering realistic reflections, refractions, and shadows.

What is a path tracing sample?

Path tracing is a rendering technology that works similarly to ray tracing in that it tracks rays as they travel through a simulated scene, such as a 3D configurator. Path tracing calculates a final image gradually using random samples.



How many games use ray tracing?

RTX delivers realistic images in over 250 popular games and applications.

Is path tracing real?

Yes. In contrast to the current implementation of ray tracing, which bounces random rays only a few times, path tracing starts from light sources and builds a more accurate representation of the intended image.

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