6 Useful Rendering Tips for Cycles in Blender!

hi everyone in this video i'm going to run you through one of my recent pieces of artwork while also giving you some tips to speed up your rendering with cycles in blender before we start a simplified version of the demonstration scene is available on the third tier of my patreon with all the third-party assets and procedural materials removed just in case you wanted to follow along and dissect it for yourself so let's begin simplifying materials the performance of your scene will be greatly impacted by the use of procedural materials of course you could bake them down into textures and i have a video showing you how to do this but procedural materials are really convenient in the way that they can be applied to an object of any shape and react to the mesh accordingly especially by utilizing the bevel and ambient occlusion nodes one thing i've been doing when building performance heavy scenes now is plugging in a temporary shader that provides a similar result from a distance but is much faster to calculate in the viewport for example here you can see that i want to use my complex iron shader from my modular metals product but while i'm building the scene i can plug in a simple glossy bsdf as a replacement it looks similar enough to still give me a good feel about the result and the increase in speed helps me to keep the performance high while still making changes to the scene because realistically when building things like this you should ask yourself do you really need to be able to see all of these extra surface features while you're still working on the modeling and the layout does it enhance your experience in any way if the answer is no then it's probably worth simplifying your more complex materials to give you a boost in performance tile size did you know that the tile size you choose when rendering can have a significant impact on the speed of your final render here i have the simplified version of the scene without procedural materials and extra details these images are exactly the same results but the left was rendered with a tile size of 250x250 with 500 samples it took 1 minute 30.56 seconds to render and the one on the right was rendered with a tile size of 64x64 again with 500 samples and this took 1 minute 46.74 seconds to finish obviously the results will vary depending on what else your computer is doing at the time but you can see a simple change of the tile size accounted for a 16 second time difference on the frame if you're rendering lots of frames then that time can really add up and just for the sake of testing i did a version using progressive sampling which we'll talk a bit more about in a minute and this came out with a bunch of sampling issues and ended up taking five minutes nine and a half seconds to render so it's definitely not worth it in the current version there is an add-on that comes pre-packaged with blender called auto tile size which you need to enable from the user preferences what this add-on does is it tries to estimate the ideal tile size for the fastest rendering speed and once enabled a button will appear in your render settings called auto tile size but even with this it may still be worth doing some experimentation for yourself to see if you can fine tune the perfect values now i can't talk about the tile size without taking a quick diversion to mention the new cycles x project which is a new version of cycles being worked on right now that makes some pretty fundamental changes to the way the engine works with the intention of making it more responsive and performant there is a blog post talking about it on the blender website and if you're interested in testing it then it's now available on an experimental build of blender one of the significant changes being made with cycles x is the removal of tile-based rendering in favor of progressive sampling basically meaning that the entire frame will be sampled rather than just specific areas one benefit to this is that you'll never have to be anxious about whether the specific tile size you've selected for your scene is the most efficient option you'll also be able to just stop the render whenever you like because samples are being cast across the entire scene so if you feel like enough noise has already been removed you can cancel it early and save the result the current implementation of cycles does have a progressive sampling mode and you can try this out by enabling the progressive refine option in the render settings under performance then tiles but just keep in mind it is slower than regular tile sampling in the current version of cycles so i don't recommend it but what i do recommend is watching the new video by rob from decoded who provides a nice breakdown of what cycles x is as well as its purpose and proposed feature set now even though cycles x is available to test right now there are still some key features missing like support for the bevel and ambient occlusion nodes as well as volumes but hopefully those will be added soon so we can all benefit from it outsourcing so this tip is a bit more about scene design and though i usually try to make sure that i'm the creator of every object in the scene because then i can share it with everyone i thought that it would be too much of a time investment making plants especially when there are already lots of places to get high quality models anyway i did think about hand modelling the plants for this scene but then again i'm unfamiliar with the best ways to shade vegetation in cycles so in the spirit of speeding up your workflow sometimes it's just a better option to use technical resources provided by other people i've got grass world and scatter for grass and small plant ecosystems but for larger vegetation i've been trying botanic this package contains a wide range of trees bushes miscellaneous other plants grass and vines the models with their pre-made shaders are easy to import with the provided add-on and i didn't need to make any adjustments to the shaders whatsoever so that saved me a lot of time there's also a tool included that lets you draw vines over these surfaces of other objects so that would be fantastic for exterior architectural scenes anyway if you're interested in taking a look at that then they have a limited version for 39 and a full version for 109 on blender market or leave my video link in the description if you want to support this channel now moving on light paths i've briefly talked about light paths and max bounces in a couple of previous videos but they're quite important to keep in mind when it comes to talking about render performance max bounces defines the number of bounces that light paths can make when obtaining information to piece to render together you can specify the number of paths for different surface behaviors separately see how we can have different values for diffuse glossy transparency transmission and volume if you don't need a high number of bounces then you should reduce them where appropriate having the total number of bounces set to zero results in only direct lighting being captured but increasing it would of course give you the indirect scene lighting as well as any extra information gathered from the transparency volume and so on sometimes it's worth testing the light bounces with different values to see if there are any issues with objects in your scene for example taking a look at our botanic plant to the left with the transparency bounces set to 2 we're getting this weird shadowing effect around the outline of the mesh but increasing the bounces to 5 makes that disappear essentially with more bounces we can get more realistic lighting you only need the number of bounces required to get the scene to look correct anything more than that might end up wasting your precious rendering time now let's talk about the render region you can isolate a specific area of the camera view to be the only area that's rendered in both the viewport and the final render you can do this by pressing ctrl and b and then drawing a box so if i wanted i could create a render region around this section of the i-beam to the right maybe i'll do this if i wanted to preview the procedural iron shader from my modular metals product i needed to make some adjustments to the visual style of it within the context of the scene you can then clear the render region by pressing ctrl alt and b this means if you want to only preview a specific area of the scene then it's very easy to do that of course by reducing the area of the scene being rendered this will significantly speed up performance but restricting the render border like this is also very useful for making corrections to a complex render when putting this final scene together i wanted a bit of light to bleed onto the plant pot on the left from behind the camera so i removed a back wall plate to let some of the sky texture bleed in however this was a bit problematic because the walls are reflective and if you look down the far end of the scene you can see how the light coming from behind the camera is being reflected back towards the camera after hitting the back wall so obviously i can't have the lie affecting the plant pot while also not having it be reflected from the back wall right well this is where render regions come in handy firstly i rendered the entire scene with the light coming from behind the camera including the reflection on the back wall then i put the wall plate back in set the render region around the end of the scene and did another render because the render region is active it only rendered that specific part of the frame and then i could save it and combine it with the original image afterwards note that when you're exporting a render that only includes a specific part of the frame make sure to set the export color setting to rgba this will make sure that all of the unrendered pixels are made transparent and then you can save it as a png see how i can now take the new frame and then lay it right over the original render now not only do i have some extra light on the plant port to the left but the unwanted reflection at the back of the scene has also disappeared so render regions are very handy for making corrections like this okay so before we start bringing this video to a close i want to talk about where the lighting in this scene is coming from most of the time i use hdris to light my scene many of which can be downloaded for free from hdrihaven.com but this time i decided to make use of the nishita sky texture which gives you control of the direction and strength of the sunlight as well as the influence of different aspects of the atmosphere you can set this up by going to the world properties tab then under surface choose background and under color choose sky texture then in the drop down you can set the sky type to nishita although there are other options available here it's worth playing around with the sun elevation and rotation because these will basically decide the direction that the light is coming from as well as its general color so if i set a render region around the back section of this scene you can see how the light is casting shadows part way across the floor and the color of the light is a pale yellow if we change the elevation from what it is now to something lower like 10 degrees then the light will reach further across the room and the color will become a more orangey yellow this is basically because the sun is setting i can make this even more extreme by choosing something like three degrees and then we can really see the effect then of course we can go the other way around and do something like 45 degrees when the sun is much higher in the sky we can see how the light has become more white if i reset the render region now we can zoom out and see how there is more light flooding the scene given the sun's new position and consequently the location of the shadows has changed so we now have more light coming in from the upper window and casting across the red bench so the benefit of having procedural skylighting like this is that it's dynamic which also means you can animate the values if you wanted to create any animation like a daytime cycle where the light is moving across the scene so those are just a collection of tips i wanted to share with you hopefully you might be able to apply some of this information to your own work remember if you want to play around with this scene without the procedure materials and botanic assets then you can grab it from the third tier of my patreon feel free to check out the page on my website to take a look what other content you can get your hands on if you found this video useful remember to ring the notification bell to stay updated with future content so thanks for watching everyone stay safe and i'll see you next time

Channel: Curtis Holt

Views: 59,876

Keywords: blender, architecture, archviz, cycles, rendering, tips, workflow, lighting, render, botaniq, tile size, cycles x

Id: Tf31Zj-GSuc

Length: 10min 5sec (605 seconds)

Published: Wed Apr 28 2021