DevLog: 82% Progress - No Spoilers

Quick reminder: You can follow development more closely on the Trello board.

Sorry for having no DevLog last week. It's a similar story this week: There's little to share, so as to avoid spoilers and also because this last scene is progressing at a solid rate with nothing exciting to share!

TLDR

• This month will be boring for DevLogs

• Last Scene is progressing! But no more sneak peeks - they'd all be spoilers 😢

• Don't read the Technical Corner - it's girthy

✅ Last Week's Progress

What I accomplished since the last update:
Last Scene Progress
Remember that there are two separate parts to this last scene: image stills and animations. While I plan on doing the animations once the still images are 100% completed, there was some preparation work that I needed to get sorted out before animations could properly begin: Temporal Denoising of Animations (see Technical Details). This did take me a few days to iron out, but you'll see that this important step will save me countless days.

⚙️ Technical Corner

Animation (Temporal) Denoising
As my journey with Blender's Cycles continues, there are still some workflow things that I'm ironing out. A very common issue with animation is that the when using a denoiser, the animation may appear to "flicker" (see the first 30 seconds of this YouTube video for an example).
Here's what's going on...
Regardless of if it's in Blender, Daz3d, or Maya, the 3D scene is rendered out with whatever the developer chooses/wants/needs; this number is the amount of times light is thrown out from each pixel of the camera and onto the scene until it hits something, or bounces, blah blah blah. This sample number could be anything: 1, 15, 999, 40612... but in Blender's Cycles, typically it'll range from 128 to 1024, taking an average of 2 mins to 10 mins for 4k image (on my 3090 or 4090). At this point, the image is actually quite pixelated and noisy and just gross - in order to get a perfect-ish render, you'd have to hit 4096 to 16384 samples! Ballparking: it's around 20 mins to an hour for a 4k image.
Here's an example of an animation that's 64 samples, which took 3 minutes to render 30 frames (1 second) in 1920 x 1080.

This is why using an advanced denoiser such as Open Image Denoise or OptiX Denoiser (no this is no generative A.i.) is incredibly important; it allows the render to be generated at a really low sample count, allowing the render to be finished orders of magnitude quicker - and they look fantastic and noise free!
Okay, "so what's the problem then? You can just use these denoisers on animations and all of the individual rendered out images!"
Here's an example of the same exact animation (64 samples), spatially denoised.
Please ignore GIF's terrible compression/color quality.

If you look at around the monkeys nose, eyes, & ears, and also the chair's gold reflections, you'll see flickering.

The problem is that these "Spatial" denoisers aren't aware of time, they're not aware of animation frames, they don't take into consideration the frame that came before it (or even after it). HOW DARE THEY!?
Most of the community tends to just say, "render the animation with more samples to solve it."
Yes... but also, that's only part of the solution.
Consider this very disheartening thought experiment: "You've got 1 minute worth of animations to render out"

• 1 mins at 30fps of 4k video

• 60 secs at 30 fps = 1,800 frames
  You've got to render out nearly two thousand frames! If each frame takes you an hour... THAT'S nearly 75 days! I hope you're starting to see the gravity of the situation 🥲

"Alright, nuii, you've made your pointers. What else you got?"
I'll keep it simple, and then I won't.
Simple: Optimize your scene so that it renders fast and with low sample rates - reduce texture sizes, bake/simplify complex environments, hide things out of sight of the camera (culling), light value clamps, and so much more to optimize! These help the denoiser perform a cleaner image and/or focus on more detailed portions of the image, thus giving a cleaner result.

Not Simple: Not only Spatially Denoise the image, but also Denoise Temporally. In other words: denoise an image frame with regard to its surrounding image frames, both forward and backward. Hang in there with me, it's just getting good.
When an image is spatially denoised, the noisy information from the renderer may be enough to provide a coherent static image. But there's this "bad, sweet-spot", where a static rendered image may look good on its own... but when animated together, very obvious and distracting flickering artifacts appear - some describe it as if the animation is "boiling." It's incredibly distracting and jarring.
Okay, so we've solved the first issue and then caused another... great. "Now what?" We continue forward, that's what.
There are so many ways to Temporally Denoise an animation; many many many of them are paid solutions such as Blender plugins or third-party software (like Davinci Resolve's Studio, priced at $250+). They all do the same thing with subtle differences.

But if you know me, you know that I want it The Blender Way™️. Because remember, the solution has to also fit in and work with my BlenderMan Render Farm! For example, there's a Blender plugin that does Temporal Denoising, but again, it doesn't work with a render farm.
What's the solution? The way that you temporally denoise an animation is to mix/blend together and get an "average" of the 3 (or 5, or 7) image frames. It's more complicated than that which includes pixel direction vectors, but that's the gist.

After all of that... using this Blender Compositor node workflow, I've got a dedicated Blender file that will help me take a noisy/boiling/jittery animation and output a clean, smooth and temporally denoised animation.
Put that into context: Instead of 75 days, I'll be able to render a 60 second animation most likely less than 10 days.

Before

After

You'll see that the background still has some remaining flickering - that's because of the volumetric haze and just a simple lack of samples; 64 samples is incredibly low, so bumping that up to 256 or 512 should make it no problem ❤️‍🩹

💬 Community Corner

I'm not sure if you're aware, but this month is February. Which houses the infamous "Valentines" blah blah - so progress will be hindered... for reasons.

Don't forget to check out the Trello board for detailed progress updates! ❤️