eli5: Could someone tell me what the big deal about RTX technology is?

Question

eli5: Could someone tell me what the big deal about RTX technology is?

In: 13

Answer 1

**What is is:**

Every 3D video game you’ve ever played has basically been smoke and mirrors. We move triangles around in 2D, in a way that makes them look 3D (similar to how someone would draw a 3D cube on a flat piece of paper) and then we calculate the lighting in a hacky way that looks kind of real, then fake shadows using a bunch more hacky rendering tricks. Each new “breakthrough,” in game graphics has just been another hack on top of the pile. We’ve gotten really good at doing this, but it’s hacks on top of hacks on top of hacks and we’re never going to be able to get that last 10% we need to be completely photo-real.

Ray tracing solves this by just… simulating the way light works in the real world (more or less) by shooting out millions of rays and letting them bounce around. Conceptually speaking it’s the simplest and most obvious option, but it’s always been super computationally expensive. Movies have been doing it for decades, but they’ve required 30-60 minutes *per frame* to render (turns out simulating millions of rays of light is hard for a computer). RTX has special chips that just do ray tracing, and have managed to speed this process up to playable speeds.

**Why it matters:**

The cool thing about ray tracing is that its **the final step** in game graphics. No more hacks, it will just get faster with each new generation and in the future we’ll be able to do more and more light bounces (slightly more realistic lighting with each bounce). It also simplifies and speeds up the development process since the artists don’t have to rely on as many tricks and restrictions when lighting levels.

Since we’ve gotten so good at doing it the old way it can be hard to tell the difference at first, even in a side-by-side, but it’s the subtleties that make the difference. Just like when you look at a wax mannequin of a celebrity: You know there’s something off, but can’t quite place your finger on it. Ray tracing gives you those last little bits that you didn’t know were missing.