5 Tips for FASTER Renders in Blender Cycles

we've had cycles x for a while now and although it's been a major improvement over the old cycles you'll still run into slow and sluggish renders sometimes in this video i'll give you five tips to improve render times in cycles so let's get started and let's get into it now for this project i have created a standardized scene which should be pretty similar to many of you guys this project contains well over 700 000 verts and also has some high fidelity nature assets containing high rest textures and displacement and things like that all render settings are currently similar to the cycles factory settings so nothing has been changed and let's get started on improving that tip number one render device now this tip might seem like a bit of a duh moment however i'm just gonna put it out there sometimes people don't know this so by default blender uses a cpu in cycles now a cpu has a big advantage and that is that it doesn't crash no matter how long it takes to render out a single frame but it can literally take ages for a single frame to render though for example this specific scene when i rendered it out in a cpu it took well over two hours and that is with a pretty pretty fast cpu not a great number there instead what we want to use is a gpu or a graphics processing unit this is a specialized piece of hardware which can really crunch out a lot of numbers at the same time to get the fastest result for rendering so let's change that right now so in here in the render properties you'll notice one thing device is currently set to cpu let's click here and change that to gpu compute now this might be grayed out for you and if it is that basically means that either you don't have a gpu enabled in blender or you have an incompatible gpu if we go over to edit into preferences in system you will currently see what type of cycles render device you are using now i am using optics which is compatible with my rdx 3070 but you might be using cuda which is the older architecture and compatible with other types of graphics cards it could also be set to none indicating that you currently do not have a compatible gpu and it could also be set to hip if it is an amd graphics card that you are using optics works best for my setup everything like i said is completely default in these settings and we are going to use this as the base benchmark just using a gpu render of this scene let's render it out and see how long it takes all right so it finished and it uh it only took and i mean only two six minutes 49 seconds and 50 100 of a second to render out a single frame so imagine rendering out 300 frames for an animation i mean it would take days however we can do so much to improve on this and that actually brings me to tip number two noise threshold usually when you hear me go on about render settings and stuff i'll talk about samples so the samples are the amount of samples that blender renders before it finishes a render now by default in cycles these are set to 4096. that's a pretty pretty high number and usually what i say okay go down to something like 150 or 300 you know actually i found out i was being a bit of a noob and there's way easier ways of doing this and that's by using the noise threshold now by default this is set to 0.01 and by default it is enabled what this does is blender will constantly look at the render and determine the amount of noise in the scene once this noise crosses the threshold blender will finish the render and start denoising it now by default the 0.01 will usually mean that it needs to finish up all the samples however we can increase this threshold by quite a bit and just letting blender determine okay unless we are below this threshold i won't finish the render i will just keep on crunching samples so that's way better than actually saying just use 300 instead let's just let blender do the magic like it always does and let it determine for itself so i'm going to set the noise threshold to 0.1 i'm going to re-render and let's check the difference all right so it finished in exactly 36 seconds so this setting alone has been such a major improvement basically the same as limiting the amount of samples but i think it went up to well over 1800 samples important to note though is that whenever you start increasing the noise threshold you will decrease the quality of the image luckily blender has a pretty good denoiser these days so it'll usually fill in the gaps and give you basically the same result as before i will show you the before and after so this is the original image and this is the one with the higher noise threshold now if it were up to me i'd say these are exactly the same images and i just saved well over six minutes of render time per frame but i'll let you be the judge of that now we can take this one step further though and i'm going to set the noise threshold to 0.5 now let's see how fast we can render out now and it decreased the render time down to 17 seconds and 4 400 of a second so again a major improvement versus using the 0.1 noise threshold also it did decrease the look of the overall image but i still feel like it looks basically the same again i'll let you be the judge of that so here's the previous image with the noise threshold of 0.1 and here's the new image with the noise threshold of 0.5 so with our gpu setup and a noise threshold of 0.5 we are now going to tip number three light paths down here we have this tab called light path and in here we'll see a total of 12 light paths so these are max bounces which you can effectively call ray tracing in blender but it has 12 total bounces what i usually recommend doing is setting all of these to one and then start cranking these up depending on your scene now this is a scene containing nature assets so we'll need a bit of transmission for the subsurface scattering as well as transparency for the leaves up here which all contain transparent images so i'm going to set the transparency 2 and the transmission to 2 and while we're at it we can also determine if our scene requires caustics now since this is a nature scene without any caustic elements in them i can just disable reflective and refractive caustics this will also save some time let's re-render our frame and compare after this did change a little bit again not as much as before it took the render time down to 16 seconds and 20 hundredths of a second as always please compare the images so this is the previous image and this is the new image and determine if this gain or decrease i guess in render time is worth the change in how it works on to tip number four performance whenever we render out a scene you might have noticed that in the upper left corner you'll see things like bvh coming along which needs to calculate stuff like all the textures being loaded in these are major time sinks for renders if we go back into blender here and we go down to performance in the render settings we can change several things so by default in the acceleration structure tab the use curves bvh and use compactpvh are enabled if we hover over the used curves bvh blender will say use special type bvh optimized for curves uses more ram but renders faster so that sounds like a pretty good thing to me depending on how much ram you've got i've got 32 gigs of ram so that's plenty to enable these types of features if you have less ram then it might be necessary for you to take the hit in render time then we have the compact bvh this one says use compact bvh structure uses less ram but renders slower now again i've got plenty of ram so i'm just going to disable the compact bvh and save on a bunch of time then next we'll have this final render persistent data and what this does is basically tell blender please store data like textures which it needs to calculate per frame in a persistent data storage and don't render them each and every time this is perfect when you are rendering still images or when you have an animation in which all elements are not animated so for instance when you have like a camera panning through a room for an arch fizz simulation and stuff you could use persistent data and it will save you a bunch of time because it doesn't need to load in these textures every time now if i re-render this frame the first time it will be the same actually because it still needs to calculate all these persistent data images the time after it will be significantly faster and i'll show you the second version all right so using the persistent data and disabling the compact bvh took the overall render time down to 12 seconds and fifth of a hundredth of a second a major major time increase over previous settings again please note that this is only something you should do for still images or for very basic animations without any moving objects if you have any of the fancy stuff going on please do not use persistent data tip number five world settings i have currently been using niche the sky texture for all of these renders which doesn't take much render time to get in there however you might be using an hdri which is pretty common for these types of scenes so let me re-render the image using an h2o right alright so after rendering the image with an hdri instead of a sky texture it took the render time back up to 13 seconds and 3100 of a second so that's a slight time increase so over here in the world settings instead of the render settings let's go over to world settings you'll have this tab called settings and in here you have this surface sampling option now it's currently set to auto we can actually change this to manual which will let us determine the map resolution now if you hover over it what this is is the importance map size resolution so every time a hdri is calculated blender calculates this important map basically determining where light should be for the least amount of fireflies within the render and it uses a resolution for that so higher values like it says over here higher values potentially produce less noise but at the cost of memory and speed and lower values produce more noise but also increases speed so what i'm going to do is i'm going to set this to 512 and this is not a guaranteed win however but it can decrease your overall render time per frame so let's see how this pans out okay so in this case it did not seem to have actually decreased the render time it actually went back up in this case 16 seconds and 96 100 of a second that's actually quite a big increase again of three seconds it could really affect the render time so it's good to know that these settings are there those are the five main settings but i have one more bonus tip for you and that's again in the light paths so let's go back into blender now let's change this final setting to decrease the render time now i'm gonna disable the environment first of all so we are back to the original settings here all right so over here again in the render properties we can go back to light paths here and you might have noticed it the previous time we were here but there's this function called fast gi approximation now what this does is it approximates diffuse indirect light with background tinted ambient occlusion this will change the overall look of your image but again comes with an increase or i should say decrease in render time so this might be worth it for your specific project i'm just going to enable it and show you the difference in render time okay so with the fgi so the fast gi approximation enabled it took down the render time for one more second so in this case we ended up with a final render time of 11 seconds and 1700th of a second so we started off using only the gpu and all default settings giving us a render time for this single frame that you are seeing right here of 6 minutes 49 seconds and 5100 a second and after changing all of these settings we ended up with a final render time per frame of 11 seconds and 1700 of a second so that's four percent of the original render time and that's insane gains or i should say losses i suppose these settings are definitely worth tweaking but you should always remember to tweak them specifically to your project so you will still get the result that you are looking for i've got a summary of all the images that i'm gonna put up on the screen right now so you can see the difference and up left will start with the first image so this is the highest resolution down at the right we see the final image which is the fastest render this gives you a nice overview to determine which type of image works for you and which settings you should apply and with that out of the way these are my final thoughts on this subject of course the best way to decrease render times is to get better hardware i use an rdx 3070 myself 32 gigs of ram and a 3700 x ryzen processor it's some pretty beefy hardware but also comes with a steep price so if you can't get your hands or you can't afford these types of hardware these settings will help you out dramatically to still increase or decrease i keep saying that your render time and make it way faster for you important to know though is that hardware does not make you a better artist it helps you speed things up it helps you save time and helps you iterate faster in your project allowing you to learn a little bit faster but in the end experience and practice are what find and make you as an artist luckily i have over 40 other videos which can help you learn and practice blender check out this one for example also please consider becoming a patron click over here it really helps support the channel and it will get you access to 40 other project files and assets that i have created i want to thank you for watching and see you in the next one this video was made possible by the following patrons thank you so much for your support

Channel: Kaizen Tutorials

Views: 343,355

Keywords: blender cycles, make cycles faster, make cycles render faster, blender rendering tutorial, blender render settings, best render settings blender, best render settings blender 3.0 cycles, best render settings blender 3.0, blender render tips, blender 3.0 render tips, cycles x render settings, cycles x render tutorial, cycles x cpu rendering, blender cycles x render settings, blender cycles render settings, blender cycles render, blender quick render

Id: VEdd9CynwQU

Length: 13min 25sec (805 seconds)

Published: Tue Jul 12 2022