Noob question. When changing the render resolution the krakatoa renders look quite different. I’m assuming krakatoa is sort of a ‘screen space’ kinda thing. So… what’s the best way to do this? Suppose we’ve done some look dev at a lower res, how do we basically up-res our work? Normally I would think changing particle size would work, but that method doesn’t seem to be available. Is the answer to always just work at full res? I suppose I should note that, in this case, our full res is over 10K wide.
its a little counter intuitive, and bobo may have a better answer, but the way i’ve worked in the past is to use as many particles as i can to work interactively at the target res [it will look grainy] and then get as close as i can. i’ve had directors buy off on full screen projected 2k renders that were grainy as hell, as long as they knew it would look the same but be smooth. then we’d partition the hell out of it to get it smooth. depending on the lighting, you would adjust your density - say if you 100x the particles you would reduce density by -100x, among other tweaks. 1000x, then -1000x and so on.
are you doing additive or lit/shadowed renders?
cb
Thanks for the reply. Lit/shadowed particles. Phong in fact. Your technique is sort of what we’re defaulting to, but it definitely takes some experience
The typical answer to this is: change the particle COUNT.
Here is an article about how we do this in Krakatoa MX with useful illustrations:
thinkboxsoftware.com/krak-it … cale-outp/
And here is the relevant topic from the Krakatoa MY documentation:
thinkboxsoftware.com/kmy-vol … rendering/
Basically the idea is that when rendering volumetrically or additively, each particle carries a density value that gets accumulated into the pixel, but represent volume behind the pixel.
Thus, the more pixels you have in the final image, the more particles you need to achieve the same look.
As you can see from the above examples, you can use a fraction of the image size, and a fraction of the particle count. You can also adjust the Density as needed to compensate when adding more particles - if you add 10x more particles, you have to adjust the density to avoid getting the volumetric density too high. See the Maya article for the exact numbers…
A possible workflow would be to generate a lot of Partitions to cover the final resolution, or at least prepare to generate many partitions, but initially create only one or a few.
Set the resolution to a fraction of the final resolution and test with the fraction of the partitions. Once you like the results, generate and load the remaining partitions (to increase the count 10, 100 or more times!) and increase the resolution to produce the final quality. If the result is still too grainy, produce even more partitions until it looks good.
Of course, if you are using Voxel rendering, the rules would be different. But I assume you are after the wispy look of particle rendering. Take a look at the above links and let me know if they make sense…
Awesome, thanks bobo. I will study the docs!
So… When do we get that iterative mode in MY? 
Maya already has most of it in the Render View menus. You can set the output to be a fraction of the final resolution using Options>Test Resolution>50%/25%/10% Settings.
What is missing is some of the Density adaptation that is performed in KMX to counter-act the change in coverage. If I can figure out how to check for that test resolution mode, I might be able to make it automatic. Otherwise, you will have to tweak the Final Pass Density in the UI yourself.
Also, we provide a quick “Particle Load Percent” value under Rendering Controls in both KMX and KMY, so you can quickly set a scene to render 1% or 10% of your particles without touching the PRT Loaders or native systems. It isn’t as fast as disabling some partitions from a loader since all particles are still being processed, just some are skipped when adding them to the render stream, but it is highly convenient for tests with lower particle counts.