[Update] Perfect Parking Spot – Shot 4: smoke simulations (Patreon)

Finished up with smoke simulation for this shot, which leaves background micros as the last thing to add in before this shot is render ready.

Smoke simulation

I simulate all the smoke for my animations in EmberGen which is a GPU-based smoke simulation software. It lets me run and tweak fairly hefty simulations on my old GTX 1660 at close to real-time, which in turn lets me simulate much bigger smoke fx than I'd be able to do with Blender's internal CPU-based simulations.

That being said there are still limits to what my old card can handle, in terms of both size and resolution, when it comes to smoke simulations, so I usually opt to break up sims into smaller parts to make the most of my hardware.

Then once they're all done, they can be imported and combined back together in Blender:

Smoke rendering and compositing

I'm opting to render the smoke for this animation in cycles, while everything else is being rendered in EEVEE (Blender's real-time renderer). While the latter does allow you to render volumetric smoke the results aren't quite as good (and come with their own limitations).

The trade-off here is that rendering volumetric smoke in cycles takes a long time and also tends to come out quite noisy without a decent amount of samples. This is why the smoke in these test renders looks grainy compared to the backgrounds rendered with EEVEE.

Once it's time for the final render I'll be upping the number of samples I'm using, as well as using denoising to clean up the results too, which will produce cleaner looking smoke while also taking much longer than these test renders.

I've currently split the smoke up into six layers which I'm combining via compositing:

These layers have each been taking about an hour or two at most to test render, so I'm expecting the final render will probably take several days. In this case though I think the extra render time will be worth it.

What’s coming up next

Along with adding in smoke I've also fixed the previous issue I was having with the traffic too. That just leaves adding in micros as the last thing to do before this shot is render ready.

Those micros will also be the last of the geometry I'll be adding to the scene, which means I can do the final renders for the EEVEE portion of things afterwards. That will provide me with the missing render passes I need to properly composite in the lights and shadows (as mentioned in the last update).

So, for the next update I'll be combining adding micros to the shot and rendering those partial renders with the required passes for compositing. The update after that will focus on rendering out the smoke at higher samples, possibly in tandem with working on other shots (depending on how long the rendering takes).