is this procedural fire or VDB

Phoenix General
1

Hi does anyone know if pixar fire and rescue used VDBs or procedural fire https://youtu.be/Vr2yt5\_X9ro?t=3m33s
If they used similar to phoenix how were they able to calculate such a giant fire with such high detail. That’s like billions of cells Thank you

2

It doesn’t seem to be terribly high detail in terms of simulation. Additional detail can be added to a relatively low-res grid using procedural noises. It is also possible to take one simulation and instance it many times in the scene.

Best regards,
Vlado

3

250mil cells isnt that big of a deal for a studio like pixar. that’s a surprisingly low detail sim, could be lower too.

4

Thank you all. Hopefully one day phoenix will be calculated by nvidia cards and we can also have nvidia works like flames etc for instant visuals too.

5

A common misconception is that simply putting something on GPU makes things several times faster :slight_smile: GPUs are good for some types of calculations and CPUs are good for other. Any real-world software which is larger than a high school student’s task has enough complexity that putting it on GPU will inevitably make some components run faster and some components run slower. Careful smart development can make the best out of both worlds, but it could also squeeze more speed of CPU-only or GPU-only implementations. An advantage of GPU implementations is the speed of GPU hardware improvements compared to CPUs - a GPU implementation would be a good investment for the future if hardware development continues the trend.

6

I have a hard enough time running high detail sims on the GPU with 64gb ram, I can’t imagine offloading those memory requirements to a GPU.

edit: This is pretty detailed for a realtime sim:

7

looks like simulation, and even not the hi-res one.
btw, speaking of hi-res fires, one widely used trick is to simulate in 2d with few bilboards in the z-direction. this allows really huge resolution, but is not good for the smoke, you have to simulate it separately in 3d grid with lower res

8

I’ve used the 2D sim from Phoenix for fire last year … worked really nice and was stupidly fast!