Dear Fellow Scholars, this is Two Minute Papers with Dr. Károly Zsolnai-Fehér.
Today we are going to find out whether it is possible to write
a fluid simulation on a computer that showcases no less than 1 billion particles!
So, is it this one? Maybe! Of course, I will tell you in a moment.
But note that there are plenty of fluid and physics simulation research papers out there. This
is a mature research field, and we can do so much today. Here are 4 of my favorite works
in this area, and then, we will talk about what is the problem with them.
One, in reality, we can experiment with whatever objects we have at our disposal, but in a
simulation, we can do anything. Including changing the physical parameters of these objects, and
thus, this previous work can simulate three jello blocks of different stiffness values. So cool!
Two, this technique simulates strong two-way coupling. What does that mean? Well, you see a
simulation here that doesn’t have it. So is this correct? Well, not quite. The honey should be
supporting the dipper, and it not only falls, but it falls in a very unnatural way. Instead, this
technique can simulate strong two-way coupling, and finally it gets this right. And not only that,
but what I really love about this is that it also gets small nuances right. I will try to speed up
the footage a little, so you can see that the honey doesn’t only support the dipper, but the
dipper still has some subtle movements both in reality and in the simulation. A+. Love it.
Three, we can even simulate the physics of baking on a computer. Let’s see…yes, expansion and baking
is happening here. Are we done? Well, let’s have a look inside. Yup, this is a good one. Yum!
And perhaps my favorite work in this area is this. Four, now, you may be wondering, Károly,
why are you showing a real video to me? Well, this is not a real video. This is a simulation.
And so is this one. And hold on to your papers, because this is not a screenshot taken from the
simulation, nuh-uh. No sir. This is a real photo. How cool is that? Whenever you feel a little sad,
just think about the fact that through the power of computer graphics research, we can
simulate reality on our computers. At least, a small slice of reality. Absolutely amazing.
However, there is a problem. And the problem is that all of these simulations
have a price. And that price is time. Oh yes, some of these works require
long all-nighters to compute. And, unfortunately, as a research
field matures, it gets more and more difficult to say something new, and improve upon previous work.
So, can we expect no more meaningful speedups at this point? Are we at a saturation point?
Well, just two years ago, we talked about a technique that was able to simulate
100 million particles. My goodness, this was absolutely amazing. And now, just a couple
more papers down the line, we go 10x. Yes, that’s right! Here is an even better one that is finally
able to simulate 10 times as many particles. Yes, 1 billion particles. Now, hold on to your papers,
and let’s marvel together at this glorious footage.
Yes, this is a scene with 1 billion. Can that really be? Well, I can hardly believe it,
but here it is. Look, that is a beautiful simulation. I love it. Now, this technique is
not only able to simulate this many particles, but it also does it faster than previous techniques.
The speedup factor is typically 3x, but not on honey buckling scenes. Why is that?
Well, the more viscous the fluids are, at the risk of simplification,
let’s say that the more honeylike they are, the higher the speedup. How much higher?
What? Yes, that’s right. On this honey buckling scene, it is 15 times faster! What took
nearly 2 all nighters now only takes an hour? That is insanity. What a time to be alive!
Now, note that these simulations still take a while, about half a minute per
frame for 150 million particles, and about ten minutes per frame for a billion particles.
But for a simulation of this quality? That is not a lot at all! Sign me up, right now!
So, as you see even for such a mature research field as fluid simulations in computer graphics,
the pace of progress nothing short of amazing. You see a lot of videos on what AI techniques
are capable of today, and what you see here is through the power of sheer human ingenuity.
So, what do you think? Does this get your mind going? Let me know in the comments below!
Thanks for watching and for your generous support, and I'll see you next time!