"Unbiased" Lighting Techniques | C4D, Octane

lighting is by far the most important factor influencing the quality of your work both in real footage and your CG scenes today I would like to talk about unbiased lighting techniques I want to show you how I light my scenes but there is one important thing I have to mention beforehand I'm using octane render engine which is a path tracer to understand the difference between rate racers and path tracers check out my ray tracing and other rendering methods video in a nutshell path tracers simulate real-world light straight out of the box while ray tracing engines give you a point of light which you have to craft and polish in order to get a good looking result and this directly affects your technical approach to artistic problems this is one of the main reasons why I use octane some of you might know I'm a lot into cinematography activity where I have to deal with lights all the time this is the magic relationship between real-world lighting techniques and pan racing engines in unbiased rendering methods the light is simulated like real-world life meaning you can use your light same as you would in real life the size of the light matters the distance to object matters and so on this is where studying real-world lighting techniques comes handy and that's why I always recommend doing so done by sliding is quite straightforward and octane is famous for giving you quite great results right away but I will show you a couple of tricks that are not that obvious in the beginning I will use this Volvo scene I made in then of 2013 let's jump into cinema 4d with octane where I'll be able to demonstrate that right then this is the exact scene I used for the video shown earlier but I just prepared it for this tutorial as you can see now lights nothing I can enable my car in there so that you would see that it's that scene if I will remove these white shaders you can see that it's my fancy garage floor texture most of the times you need a base light which can be enough an is an HDR eye map so let's proceed and create one-click objects HDRI environment and specify the path to your agency or I map in my case I just use night scene HDR I and it gave me my base reflections here we go that's looking good already but it's obviously not are directed in any way and it doesn't look like production shot or anything let's disable the car and talk about lights themselves a bit I will just put my white shader back on the environment elements quickly and create a sphere so here we have a sphere let's create a light objects light octane area light okay that's that's exactly what you're doing most of the times and it's absolutely fine but there are a couple of crucial things to understand about the light in its behavior let's put that car paint shader on the sphere to see what's going on you see that reflection is quite harsh it's just white rectangle evenly lit surfaces does not exist in the real world so you would always want to use a texture or at least a fall-off for your lights this will help you achieving soft light gradations and much more interesting with reflections on your model so let's go to a light tag and in distribution let's choose octane fall off like so and straight away you see the big changes let's go into the settings and change the minimum value let's compare it to what it was that's what it was and with fall-off not a lot of changes but I think it's not the most suitable context for showcasing that this technique basically what this allows you to do is to get the soft gradations of your shadows instead of harsh circles or squares and what's happening is because the fall-off is set to react to cameras position it changes its brightness depending on the position of your camera see in case of reflection light interacts with the object that is reflecting it if I would change the mode to normal versus vector and choose 90 or 180 degree it will change the fall-off and this can be used in other scenarios as well yeah depending on your scene I'll just leave fall-off alone for now the next important thing is the distance you see the shadows are quite soft no matter how far away the light is and this is because scaling is very important in unbiased engines if I'll turn on the preview of my car you see that the spheres almost the size of the car so let's shrink it down a bit let's make up something like 20 centimeters and here we go now the shadows are super soft let's let's click options and uncheck check camera this will allow me to navigate in the viewport but without affecting the live viewer Oh our light is still really big and this is why our shadows are super soft the size of the light is really important let's create something smaller to try to replicate something like this light here I know that it's 15 centimeters wide and maybe about 10 centimeters tall maybe even smaller but who cares so I'll select my light and go into details and their size X would be 15 centimeters sighs why would be 10 and of course the intensity of the light went down so we will increase it a bit and here you go straight away you see that that directly influence the softness of your shadows so the smaller the light source the harder the shadows the bigger the light source the softer the shadows the difference is pretty big so in order to get realistic shadows and stuff I encourage you to Google real world production lights and their dimensions now you see that the distance to object matters much more a light properties like size and distance also directly influences the effects like caustics and wallet metrics let's quickly create something different from the sphere I'll just create a platonic beveled edges duplicate it and make the duplicate 10% smaller and then I'll merge those two and now I'll drop a glass shader on it the reason I'm I did a duplicate of the Platonic is because as physically correct engine octane cares about the volume of your objects so if you want to replicate real glass it can be just playing it has to be cube or something would that make sense has to have volume in it in order to be calculated properly so with a small light source you see that caustics are calculated quite good and again I don't think it's the best context to showcase the effect the best context would probably be something like rippled water you know that effect you have at the floor of the pool or that caustics but yeah for caustics you usually need small light sources or the Sun that's all good let's increase the size of our light and see what what will happen I'll change the fall-off of my light and as we are increasing the size I'll decrease the intensity of the light the lights or size dictates how pronounced is the caustics effect in this case let's make a comparison let's reset their light size to its default and decrease the intensity so you see massive light source produces no caustic effects it's just a subtle soft shadow this is what it was with a small light source and this is what it is with the big source quite a big difference let's bring our small light back and let's duplicate it and move the big one quite far away I'll go to big lights a light tank and decrease the intensity again and now I have a combo of those two I have nice soft shadows plus pronounced caustics effect let's move this light a bit further away great thing about 3d in general is that you can have angles and light positions as which you can't achieve in real life in this case let's go to small lights light tag go to visibility and uncheck camera visibility and we just hide it that's the best cheat in humankind history and this is the reason why a lot of companies comes to CG artists for their product visualizations because real world photography and videography just can't produce such results that's all cool and great next thing I would like to talk about is lights relationship with volumes in Achtung so let's just leave our small item and in our HDRI tag let's go to medium and add fog by default it's quite thick so let's ready to use the density point one point one looks good let's increase the intensity of our light and here we go we have a lovely light blob this kind of effect is what you may be after but understanding real lighting can help you to have a lot of control in a lot of conditions this looks fine but what if I would like to have something like a spotlight let's click compare store render buffer to have our frame for comparison I'll go to my light properties change the area shaped disc and in order to have a spotlight you need to block the lights direction and what I'm usually doing is I'm dropping the tube around my life control click on the tube so it appears on the position of our light and let's scale it down but already you see what I mean and I usually drop a light blocking shader on my tube and this is just diffuse material with pure black color on it and all other channels are disabled this ensures that this object is not participating in any calculations it's just blocking the light and here you go you have your spotlight just like in real life just by blocking the light you can direct it in a much more controllable manner but if you would like to get a narrow beam of light well just stretch your light blocker here you go this was our original spotlight and this is our new one more directed one now let's create a second copy of this line and the second one I want to I want it to be smaller you probably noticed that sampling rate parameter in your lights and I really think that major part of achtung users done doesn't understand what it's for you may even play with it a bit and notice that if your increase it it makes light a bit more intense but in reality what it does is it's balancing noise patterns when you have different light sizes in your scene I just made our big light three times bigger than our small one and by default they have sample of one each and you that the left one the bigger one it resolves faster while smaller one have more pronounced noise in it if I will go to our small us to our small light and increase the sampling rate if it's three times smaller than I need three times more samples and now you see that they're resolving equally I think that's a really important thing for everyone to know that's all nice and good theory but damn Andrei what did you do in your car seem with the reflections and stuff well for fun sake let's just quickly recreate the lighting of this scene I'll an eyeball my car and as I mentioned my base light was HD all right let's start shaping our car with lights let's pick up a good and sexy angle oops okay this looks good options uncheck check camera so one of the most popular lighting techniques is called three-point lighting where we would have our key light our fill light and our hair light there's no Heron car but it's just the name so this will be our key light sort of we're dealing with car here so it's not a portrait you know you ever seen real-world car photography studios there are super big soft boxes in there so I'll scale this one quite I'll make this one quite big and again use the fall of ups not cinemas for these fall off but Octane's fall off and the light almost completely disappeared as I said in each particular unique case you would need to play with your lights a little bit in order to make them look good let's increase the intensity and this will be our key light highlighting the wheel and a little bit of reflections on the wing I don't want it to really light the rest of the car so here we go our key light done let's create another light and this will be our fill light again kind of in traditional three-point lighting fill lights supposed to be complementary light to your key light which implies that key light is much more intense okay that's looking good but some shadows we may leave it like that to be honest let's try fall-off okay that looks fine now we need to highlight the shape of the car somehow let's duplicate the slide click PSR to reset our position rotated 90 degrees and put it directly above the car like in real world badass studios uh-huh let's reduce its intensity a bit and here we go we have quite sexy reflection on our car let's disable visibility of world of of all our lights remember the best cheat and the history of humankind I like it and also stepping outside of three-point lighting a bit and going a bit into light direction side of things we need to somehow light our background let's create a regular light and move it to our wall behind the car point it to the wall something like that maybe move it a bit further away from the wall let's decrease its intensity a bit let's create another light and put it exactly behind our car this one actually supposed to be our hair light the one right above the car is just an addition just a necessity for a car photography okay so our hair light back light whatever and again the reflection is quite harsh so light settings distribution fall off like so here we go that looks like a decent hairline and you see it created a light stripe on the floor behind the car which is also quite nice every scene every environment is unique so instead of asking how someone lit one particular scene you better start thinking how light works in real life this will massively help you and your projects if you're working on a video or something for each particular shot you would need to adjust your light just like on real-world set I think that's it once again my biggest advice to you is to learn unreal or lighting techniques as a bonus to this tutorial I decided to publish my shaders I used to shade my car in this video the link is down in the description I get you can buy it as usual thank you for watching and I see you soon [Music]

Channel: Andrey Lebrov

Views: 186,637

Rating: 4.9699955 out of 5

Keywords: lebrov, cg, vfx, tutorial, how to, learning, filmmaking, step up, master, lighting, light, unbiased, technique, c4d, octane, pathtracing, shadows, falloff, volumetric, automotive

Id: TuKDhZU7ySE

Length: 18min 14sec (1094 seconds)

Published: Tue Aug 20 2019