Why is Real-Time Ray Tracing a Big Deal?

Erik Quintanilla
4 min readAug 24, 2018

P erhaps anyone who games has thought about why it is that animated movies look so good, meanwhile their Xbox games look like some 12 year old sketched them up? The difference is ray tracing and Nvidia’s event at Gamescom was major, although it seems like not everyone is sold on the idea of real time ray tracing being revolutionary. The purpose of this article is expose these ideas and detail why this is a major, important step.

So, what is ray tracing exactly?

Ray tracing as it has been used for decades now is, rather than using “point” lights everywhere and lighting rooms by having everything in a game be of a constant light intensity with only a few “real” lights, is trying to simulate light by tracing rays of light and for every single place that this ray of light lands on, depending on the material/texture that it is, absorbs or reflects light like in the real world. This means for every ray, and object that it comes off of, we must calculate the angle and trajectory, this is why the number of rays/s is a big deal but this will be discussed more later.

Image by: Nvidia Corp., Unreal Engine Demo Featuring Ray Tracing

This, as you can see in this Star Wars demo, does end up looking extremely good in the world of computer graphics. But if this looks so good, why have we not done this the whole entire time? The answer is this is majorly expensive computationally at the hands of feeble hardware like mentioned above, would have to take hours/days/months just to render a scene, see your mistakes, correct, and repeat when being animated. This was never possible to have done immediately and get instant feedback in these demos, it all had to be pre-rendered then only after it was done after some time, could we see the end result, until now.

What Nvidia unveiled at Gamescom was major: not only for those in artificial intelligence, but because of the rapid pace at which one could now do, what used to take days/weeks into something that can now be done in real-time for a video game. This has been along time coming for me, as this now means we will now have photo realistic games very soon. In other words, this is bringing animation studio quality computer graphics into our video games to be done in real-time, rather than having this fake lighting discussed above.

Why Nvidia’s RTX GPUs are groundbreaking

The major selling point of Nvidia’s new GPUs are not only the artificial intelligence portion of them, but the other major selling point is that we will now have the potential to have Pixar-quality games at our disposal. Not only this, creators of this content won’t have to wait days or hours for their scenes to render, meaning our favorite animated movies will be coming to us quicker also.

Image by: Pixar Animation Studios

Not only are these GPUs faster in the traditional sense that they render the usual games with the usual lighting schemes faster, but you can also realize the need for a new comparison model: all new games in the future will be ray-traced.

Image by: Nvidia Corp.

Obviously they’re faster and a little pricier but this is a new avenue to go down, this is much like when games could finally be played in color, or games could finally be played in high definition. This is the future and there had to be a new standard to see the relation of performance between the cards: gigarays/s. From the portion above I imagine you understand now why it is important that a GPU can handle more rays/s, the more rays we have, the better the scene is, and the more power we have to spend on other effects within the game.

Admittedly, some of the demos shown at Gamescom were not the best, but these are only preliminary and perhaps hastily made. Regardless, this is a very important step in creating worlds that are more immersive and realistic, however, there are several other equally important hurdles that have to be crossed as well that have not been well addressed. Such as how a game moves and the ‘life’ inside a video game is also something that is still meaning to be done well. Nevertheless, we are closer than ever before at having a game that at least looks like it breathes life.

TL;DR: The future is ray tracing, and these GPUs usher the new era in. Ray tracing has been used for decades in movies from Pixar, Disney, in 3D-animated movies but it is only now that we have the opportunity to have this technology in our video games. As game devs get more familiar and incorporate the technology in, we will see better and better looking games, all because of ray tracing.