Advanced Lighting Tips for Cycles in Blender

hi everyone today we're going to be talking about some advanced lighting techniques in blender with the cycles rendering engine for other video I'll be showing you a variety of demonstration files so you can pick up on Gumroad there's a free and a paid version of the package the free package contains simple demonstration scenes or is the paid version contains more fleshed out artistic scenes so you can dissect to see how they were made before we start I should also mention that Martin from CG boost has also recently done a fantastic video about lighting characters for storytelling so if you're interested in this subject then I can highly recommend checking that out as well but in this video we're not gonna be talking about lighting for a specific type of artwork instead I'll be showing you a few rendering techniques and features that can quite often get overlooked most of these are specific to cycles because it's path tracing engine whereas evey being a rasterization engine doesn't have the same fidelity when it comes to simulating the physicality of light the first thing we're going to talk about is transmission transmission is essentially a measure of how much information behind the object can be seen for it I think most people only think to use transmission when creating glass or polish minerals of some kind but I'm here to tell you that the applications of transmission are far greater than just that see here how we have a curtain in front of our character module behind the character is an emissive light source which we'll talk about there later light is able to pass through this curtain but not all of it and that's the key point because by controlling the physical properties of the material we can get these cool faded light bleeding effects now the keen-eyed amongst you may have also noticed I've reduced the Alpha value on this principle psdf shader that's because transmission alone might not let you see as much as you want to by balancing the two we can get a good compromise between visibility blurring and light bleeding see what happens if I leave the alfrid 0.7 and reduce the transmission all the way we miss out most of the light bleeding and blurring likewise if I increase both the transmission and the alpha to their maximum values we get both the bleeding and the blurring effect but the blur is very intense probably too much to identify the proper shape reducing the alpha value from here progressively reduces the blur until we're back at our original effect so what kinds of things can this be used for well immediately this demonstration gives me ideas for a medical lab with draping plastic separators where we can give Larry glimpse of an operation happening behind if we jump over to one of the paid demos you can see how I've used transmission to load the back railing leave we impression on the curtains but there's something more I can show you because of the wonderful power of nodes we can apply all sorts of generative or mathematical processes to change the look of the transmission you can see here that I've got a Voronoi texture with a colorant plugged into the transmission value the mapping coordinates are generated from the camera transform on the Voronoi arming the scale - and then randomness zero now you can see these squares which are areas where the transmission value is lower than the surrounding area taking advantage of this you could create some really cool materials and surface effects okay now we're going to move on to light bouncing which might otherwise be described as global illumination but we'll call it light bouncing because it's an obvious description what I'm talking about is how light and color data bounces from one surface onto other objects in the scene now this isn't much of a secret but I know the quiet off people don't often think to use this kind of illumination as an actual technique for lighting a subject see here how the light from the brown floor is bouncing back onto the faces of the character that are pointing downwards this is a perfectly viable way to emphasize the contours of a shape just to demonstrate this more let's take a look at the position of the lights in the scene here you can see that I have two area lights behind where the character is a purple one is pointing diagonally upwards filling the scene with color and a white one is pointing diagonally downwards the light from this one will create a highlight around the character and the excess light the histor floor will bounce back up you'll also notice that we have a week of volume permeating throughout the scene but we'll talk a bit more about that in a minute to increase the strength of this bouncing effect there's a few things we can do we could increase the strength of the upper light however we know this would also increase the intensity of the highlight around the character we can see this now if I turn the power up to 5,000 of course everything is blown out and not very balanced at all the second option is to change the floor material again for the sake of demonstration I have just a basic principle psdf shader if I increase the brightness of the base color value then more light is reflected back up to the character as we can see here and because color data is also carried by the simulated rays if I change it to a different color you can see how this is also projected onto the character as I said a lot of the time people don't really think about this kind of bounce lighting it's just something that happens regardless of what you do and if it looks good then that's a happy accidents but if there's anything I want you to take away from this it's maybe try to learn to use the side effects of renderer as an artistic tool now before we move on to the next demo I just want to quickly mention the presence of the volume in this scene this is set up through the world nodes and I use volumes to create background gradients in scenes they need empty space filled if you keep the color of the volume grayscale then it will accurately adopt color of the surrounding light objects the brightness of the volume in any single area will depend on its closeness to one of the lights and this helps to make the transition from a highlight to empty space more natural see how strange this looks with the volume disabled okay now we're gonna move on to one of my favorite features in cycles and that's lighting by emissive materials let's open up one of the demos in the free version a lot of my work relies on physical emissive elements and being able to use them as light sources opens up a huge world of possibilities it's quite often been the case recently though my artwork does not use any traditional light sources no lamps no HDR eyes only emission and reflection so let's talk about why with traditional lamp objects you are restricted to a finite point the light can emit from every lights are cool because it gives you a larger surface for light to emit however I'm sure those of you they've used them before know that as you increase this size you oftentimes have to play with the strength value to get it looking right and that's a little bit tedious but a benefit to area lights is that they don't show up in renders as physical objects but what I like about using emissive materials is that they do have a real physical presence it's consistent and because the lighting is controlled by nodes it means that you can get super creative and mathematica with it if you really wanted to light emits from all across the material and just to prove this I can change the color of this emissive strip from plain white to a gradient of pink and blue see how the color blends so well across this entire room if he tried to recreate this with lamps alone it would take a lot of trial and error and once you've got it right it would be a pain to change anything I said it once and I'll say again emissive light is one of my favorite features of cycles by seeing it in a closed demo scene like this is all well and good but what about using it for actual artwork will come with me over to one of the files in the pay package some of you may recognize this it's an adaptation of one of my demos from the modular environment design with blender video all of the light in the scene comes from emissive materials there are no lamps or HDR eyes whatsoever the only downside for having this much fidelity with the lighting simulation is that it takes longer to render you can see that as I moved the camera calculating the samples is taking longer than the previous demos combining this with highly reflective materials also get some really cool effects as take a look at the last paid demo this was a piece of environment art that I didn't end up putting into a video of its own you might have also seen this in the thumbnail for my recent video on procrastination and I briefly showed it in my first live stream unlike the last demo there is some extra world lighting going on but it's not an HDR I just white fill light however there's a lot of emissive material lighting going on you can see clues for this in the reflection of the spheres on the right if I move the view pool camera around you can see the strips laying on the ground of the scene and these are providing some highlights and some interesting reflections for the objects okay so let's combine the techniques that we've learned so far and see what happens I've taken one of my previous character concepts called Sargent butters which you can go on Gumroad app into the transmission demo from earlier as a disclaimer this file is not included in the demo packages you have to pick up the character separately ok the last technique that we're going to talk about for this video is less to do with lighting color and more to do with pre-emptive compositing sometimes you might want to render an object that's being influenced by an HDR eye without actually having the HDR I showing up in the background of the render this is something that's quite easy to achieve by only using a few nodes and I use this all the time if we take a look in the world modes for this last free demo you will see the surface of the world is a mix of two shaders one of them is an HDR I provided by HDR Haven calm which I highly recommend you go and check out the other is a basic RGB color node to tell the renderer which of these we want to be the background of the render we need to create a light path node and then plug the is camera ray output into the factor input of the mix shader' node now the HDR is no longer being displayed as the world background even though the objects are still being affected by it okay let's take a minute to talk about the sponsor for this video which is sketchfab you may have really no sketchfab for providing the best Freedy model viewer for the web you might not know that they actually have an online store for buying and selling 3d models you can use the built-in model inspector to preview the geometry of the mesh on with all the textures so you know exactly what you're getting there's a wide variety of content available and a good number of dedicated artists providing high quality content if you're interested in maybe selling your own models on the store then you can also consider applying to become a seller so thanks for sponsoring this video Sketch up not just before we close this up a few days ago I put a notice on my Instagram seeing if anyone wanted to get some questions answered in this video so I'll answer some of those now while you watch some footage of my recent walk through the English country have you considered doing a video about animation nodes slash virtual course or car yeah I've actually already done a video on animation nodes but I don't have that much interest in doing another one in the short term don't get me wrong the add-on is fantastic and it definitely suits my interests however that single video that I did is responsible for nearly half of all the troubleshooting requests I've received which is quite impressive given that I distribute tools and - add-ons for blender it's largely due to a version mismatch and it features a vive blender or animation nodes being changed over time so I've said to people that I'll do my programmatically node stuff when everything nodes becomes an integrated and stable thing in blender if it ever does as a content creator how do you manage working free time do you work at a specific time or whenever I don't have a specific time I just work whenever I want to I tend to get most of my work done within a few hours of waking up but I don't force myself to work on something if I'm not really interested in it this is something that I did actually talk about in my recent discussion video on procrastination when will you go live again probably sometime within the next month I did enjoy quite a lot last time it was really nice to have a more organic conversation with the audience and it was also quite off on having like CG matter and the others along as well and for the last question I'll answer what is your favorite video game of all time well I've got quite a few favorites but I think the award is the tie between mercenaries playground of destruction and the second ranch in Clank game which was actually given a different title here in the UK compared to the USA ok that's where we're gonna leave it for this video don't forget to pick up a copy of the free resources and if you want to support me then you can pick up the full version of the package if you enjoyed this video then make sure to follow me on all the platforms to keep up to date with new content and links for everything can of course be found in the description so thanks for watching have a great day and I'll see you next time [Music]

Channel: Curtis Holt

Views: 92,229

Keywords: blender 2.8, resources, tutorial, download, lighting, cycles, materials, realistic, eevee, nodes, curtis holt, free, light

Id: p01wph5dZfs

Length: 11min 1sec (661 seconds)

Published: Mon Jun 01 2020