Renderman 23 Render Optimization Tutorial

hello michael here from small robot studio with a quick optimization tutorial for renderman 23. um so today we're going to have a look at how to optimize your renders just some simple things that you can do to improve your render times this is really good if you're doing animations with lots of frames recently i animated a short that was a minute long and it had about 1300 frames so obviously every second that you're spending spending rendering a frame is multiplied by however many frames you've got so that's 1300 seconds if you take one second off you save 1300 seconds and the overall render which is 20 minutes or something like that in your total rent of time so every little incremental thing that you can do adds up for these big renders so i'm going to look at a couple of things that you can do to optimize your renders and they're pretty straightforward so the first thing we'll do is we'll have a look at our renderman preferences and you want to look at render threads mine's set to negative three at the moment normally you'd have this to probably negative one basically this is saying how many cores you're going to use your cpu cores and i'm going to use all my calls except for three negative one is probably the best way to go i'm using negative three at the moment because i'm recording this so um while i'm recording i'm obviously need some cpu power to be able to record at the same time and even at negative two my computer still doesn't have that good a time so i've got that at negative three and um we'll take a baseline render of this scene that i've got here it's pretty simple and we'll see what we can do with it so i'm going to set it to a sample rate of 64 which is um fine and a minimum samples of eight usually rule of thumb actually if you set this to zero what will happen is renderman will square the max sample rate so in this case it would be eight so it's the same as setting it to eight here you can set it to a higher sample rate if you are finding that you're getting too much noise anyway and the other thing that we want to look at is pixel variance pixel variance is going to look at areas where renderman is detecting a lot of noise areas like shadow and specular highlights usually tend to be these sorts of areas high contrast sorts of areas um and it's going to spend more time rendering them so if you reduce the pixel variance to be even lower say 0.001 it's going to be it's going to provide you a cleaner render overall 0.01 is probably fine if you're using the denoising as well otherwise you've got path tracing parameters i've got my indirect bounces set to 3. every light source is going to emit what essentially every pixel on your screen is going to be pointed path traced towards a light source so in this scene i've got a light over here and what's going to happen is renderman's going to shoot say from each pixel on the screen a line outwards until it finds that light and it's going to sample that pixel based on that light position and the things around it um and to give you a result and it's only going to let each path bounce three times before it bow bounce indirectly three times so you'll always get the initial hit it's directly out of the screen but the say if it bounced off this wheel and then hit the ground and then hit the wall and i hit this door and then went to your light or whatever then it would get those extra bounces and that would accumulate some extra color in the light ray so particularly if you've got you know highly specular or very bright colors nearby you'll start to notice that areas around them will start to have those light those colors reflected into them so for this indirect bounce set 3 will be fine for the scene if you reduce it too low uh you'll notice that your your scene starts to look a little bit muddy and darker actually because there's less technically less light being rendered so yeah probably minimum three for most scenes but that is somewhere you can start um the integrator we're using is the path tracer i'm not going to worry about looking at any of the other integrators for now because i'm just going to work on this one scene different scenes may call for different integrators if you're looking to render call sticks you want to use vcm um i'm not here you can also render call sticks using the path tracer but allowing caustics isn't recommended is actually more less efficient to render it with the past path tracer that way when you're doing your render optimization make sure you're denoising basically always if you're not you're spending more time rendering each frame where you could just render it 75 of the way to looking good and get the denoiser which is very quick to finish up the last 25 of getting it to look smooth so i've got my beauty layer selected there and i have got denoising enabled if you want to learn more about aovs which is what this is you can check out the aov tutorial that i did recently so we're going to do a final render now we're just going to click this button here and it will tell us how long this is going to take to render to 64 samples okay so the render is complete and it took 1 minute and 49 seconds so that's quite a long render time for a fairly simple scene unfortunately i'm not able to render with all my cause otherwise it would be quicker we can see though at a glance that there is a bit of noise i will note that the material for the car is actually has got a flake material to it so all these little dots that you're seeing are actually part of that material and materials are actually a big part of your render optimization determining whether or not you need to have things elements like this whether they're going to be visible or you know important in your final render or things like subsurface scattering if you need to have them subsurface scatter um things like that um we can have a look sort of preview what the denoising might be able to take here by hitting the n button on the keyboard and you can see it pretty much cleans up all the reflections in the ground there and most of the elements of the car um there's some minor noise here that has been cleared up but also what's happening is the denoiser is looking at all this these um flake reflections in the car paint and it can't determine whether that's noise or intended so it's looking at this and thinking okay that's noisy i need to do something and it doesn't really do a great job because it doesn't actually know that whether or not that's noise it looks like very heavy noise but it's actually just the material so that's one thing we can do to take care of this and you can tell how much the denoiser will do just by looking at some of these cleaner areas here so this is this is still fairly noisy too noisy for production if i had the denoiser on that's pretty much production ready now so even at 64 samples that's pretty clean so if we replace this material with something that's similar without maybe these flakes it would be a lot better and then we can compare that but there's a couple of other things that we'll do first you know just to give you an indication of the time you can save under the advanced tab we've got render options here and the thing i want to focus on here is the bucket size just increasing your bucket size to 64 by 64 actually can cut a couple of seconds off your render time overall and looking at our sampling we've got our pixel variance at 0.01 we'll increase that to 0.05 say that we're reasonably happy with this area here so we'll get it to 0.05 and see what that looks like and allow it to run for 64 samples again and just as a note i to bring up your inspector and c to bring up your catalog all right so with the only thing changed being the bucket size let's compare our render times we went from a minute and 49 seconds to one minute 20. so we're saving 29 seconds just by changing that bucket size which is incredible really and it's something that's really worth noting we can go a little bit further though we're going to work a little bit on our material here for a moment so we're just going to jump into the hypershade editor very quick beside you used flakes into the bump normal so i'm going to take that out of the specular and now the specularity should just be nice and smooth um and we'll still get this incandescence that i had in the car anyway so we'll render that again and then we can make a determination okay so we've taken the um specular bump out and this is a comparison so it does make a big artistic difference so you need to decide what you're looking for this could possibly this effect could be doing it doing it done a little bit better with maybe facing ratio rather than the um rather than the flakes just to get that blue highlight on the top a bit more but this could be considered absolutely fine and looking at the inspector we'll see that our render time is only a minute and six seconds now so we've chopped another 15 seconds off with it which is huge so we have a look at the denoised version and it's not looking too bad um this is obviously zoomed to 300 so it's not a really good indication of fi of your production quality but you can see some unusual it may or may not show up on the on the video but i can see some sort of blurriness in there which doesn't look quite right so what i need to do and actually here that reflection looks a bit unusual so what i'll do now is i'll reduce that pixel variance again but why don't we have our max sample rate and then we can have a look at the difference between those okay so let's compare our last two renders so this is at 32 samples and this is at 64 samples so definitely 64 samples was cleaner but we have also remember reduced our pixel variance to 0.01 so let's look at this area here for example so we zoomed in 330 percent so not a huge difference this noise here is definitely more coarse than the noise um in the 64 summer one so it might end up being that 64 samples is the the baseline for us but we'll have a look at it at the hundred percent and use the denoise preview and compare the two that's actually come up a lot better in the 32 sample version with the pixel variation variance set to a lower target as you can see and it's fixed this now using the the optics denoiser and the preview is not 100 fair because it's not the same denoiser that's used when you do a final batch render it's actually i think the height disney hyperion render denoiser i think but i can't recall exactly off the top my head what it was called it's not the exact same one though you can set it to gpu as well which i've covered before in previous tutorials but i can redo for 23 if you are interested let me know in the comments so let's see what the render time is 52 seconds at 32 samples so you know we're starting to see going from a minute and 49 seconds to 52 seconds we've almost saved a whole minute per frame now if this was an animation so a big big difference obviously if it was 1300 frames or whatever it was that so that's 1300 minutes that you're saving the other thing i will just quickly show you is we'll reduce the max and direct bounces down to two and we'll do one more render here and have a look at what it does okay so this is finished and our render time is 47 seconds so comparing that to the previous we're saving another five seconds however you can already see what's happening here with our areas that are refracting and reflecting light um this headlight here which has got its headlight on and there's a light behind it transmitting through we're not actually getting as many um bounces there's some reflective material in there as well and also these areas here which are like a a refractive plastic um aren't refracting any light anymore um it's reflecting light off the front face but because there's no light in front of this you can't see it so worth mentioning if we compare the two though you can see also the difference that the um amount of light is is occurring so generally it's more realistic um to have more bounces there's an infinite infinite amount of bounces light can take theoretically um given it's if it had infinite energy um but obviously that's diffused over time um but if you hit the denoise button it looks okay possibly passable depending on your situation and it will also depend on your materials like i said earlier i would say for this one at a bare minimum i would want 32 samples i would want three bounces uh this is only rendering at um hd 540 because because obviously i i'm recording this and um doing record and rendering at the same time which is taking adjust the recordings taking about 10 of my cpu so that's worth noting make sure you've got nothing else running on your computer and um also when you're when you're rendering make sure the denoiser on the it previewer is off it will render a little bit quicker that way as well and one other thing you can do with your renders just while i remember is on your final render you can deselect incremental and what will happen is it will render up each each bucket which is each little square that appears at a time um and that can actually save you a little bit of time it saved me one second compared to the um the other 132 samples so worth noting not a huge difference but every second counts obviously when you're doing animation so we went from a render time of a minute 49 to a render time of 51 seconds with a material change which obviously made it look a bit different but this is an artistic choice possibly that you can get away with and then a few basic changes in our render settings so hopefully these help you guys out there that um i know i get a lot of messages from people that are going through university at the moment and they've got a um a thesis or a final product project or whatever to deliver and it's an animation and they're rendering it and uh they're hating life because every single frame is taking five minutes so hopefully this is 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Channel: Small Robot Studio

Views: 2,743

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Id: hCPtuWYIqvI

Length: 15min 38sec (938 seconds)

Published: Fri Oct 09 2020