Photorealism Explained

if you've ever flicked through an ikea catalog it might surprise you to learn that 75 of the images in the catalog are actually cg renders sounds crazy but it's actually true ikea realized that switching from photography to cgi allowed them a lot more flexibility over the final image because they could make revisions and changes after they'd finished and also it saved them a lot of cost as they didn't have to hire teams of artists on one specific day to all shoot one particular set doing it on the computer yeah resulted in much cheaper costs so ikea is just one of many companies and industries that are realizing the benefits of cgi so we're going to be discussing something really important to all ct artists one of the most important things for a cg artist to learn is photo realism it's a topic that you guys have been requesting like a year ago i put out a survey and this was the number one thing people wanted to learn about so we're going to be discussing why it's so important why should you care about it at all the four building blocks necessary in order to achieve photo realism and some simple tips and tricks that you can use to make more photo realistic renders so um yeah so throughout this video i'll be recommending some ideas as well as some of my own products but only if i think they will actually help you so let's get into it kicking off with why why should you care about photo realism well it's no surprise that hollywood loves themselves some cgi but to an extent that might surprise you um there are things where you watch a movie and you you think you know for sure that has to be real um but quite often times it's it's not unusual for them to replace entire sets with cgi for the same reasons that ikea realized and allows them much more flexibility over the final result and often very very reduced uh cost um costs overall as well as that lower budget productions like tv shows i mean game of thrones not really low budget but uh lots of tv shows uh to a point that might surprise you are now switching to doing a lot of things now in cg even when you think like as if that would be cg then just standing on the street location costs and things like that makes sense to switch to uh to cgi it also allows directors and people to tell stories that just otherwise would not ever be possible like benjamin button this was a movie that uh like the story was written years ago and it's been kicked around in hollywood for apparently like 50 years people have been wanting to make a movie on this but all the ideas that they suggested like you know using different actors of different ages they were all rejected until finally in 2008 the technology was there that they were able to put together a tech demo which was so convincing that investors gave it a green light so they were able to finally tell a story that directors had wanted to tell there are cases where cti is it's the only solution there are even other industries that previously had nothing to do with cgi and now get realizing the benefits so vr and architecture they're being fused together to create real-time architecture walkthroughs so imagine this so say you're having a house built and normally how it is today you go in there and they'll draw out some plans and explain to you how the house is going to look but it's very hard to envision it so there are there's a youtube channel unreal engine for architecture you can click that link down there and that will show you the video just amazing it's real time architecture and you can walk through the building so it's going to help sell homes so this is a new thing which you know previously had nothing to do with cgi now getting involved in it games of course i mean they've been cgi for years uh but the number of gamers that are into it is staggering in 2014 a report showed that compared with um raw box office ticket sales games outsell movies which is uh really crazy so basically if you were to look at a graph of usage of time it would look a little like this whereby as technology has gone up cgi has made its way into more and more industries and in a lot of cases some of the jobs that were previously going to you know photography and you know the ikea situation i have now been kicked over to uh the cgi team which of course is great news if you're watching this chances are you're a cg artist and that means you've got a lot of opportunities uh awaiting you however it also means we all need to collectively lick our act lift our game because they all want photo realism every example i've just mentioned relies on photo realism ikea for example wouldn't get by if the images looked sort of okay sort of realistic it has to look like a photo so the customer can't tell the difference when it comes to movies hollywood relies on photo realism because otherwise if you've got a live action backplate with a cgi element and the cgi doesn't look photo real they don't mix and it becomes jarring to the viewer video games as well rely on photo realism of course as many different styles of photo realism sorry many different styles of video games but the aaa studios often battle it out for the most realistic game of the year because that is what players are drawn to they want an immersive experience it's why every game review gives like a graphic store uh score um it's why trailers and tech demos they always capture their most realistic scenes and even if you're not interested in working in the industry just want to make some cool artwork to share with your friends online photo realism is also a great way to turn heads like this awesome image by cornelius damrick so all this is to say i personally believe that photo realism is the most important goal for cg artists if you're trying to get in the industry or even just get good as an artist photo realism is the number one goal that you should be focusing on controversy but what about so uh whenever you bring up photorealism people say yeah but what about disney what about pixar what about dreamworks what about xyz what about all the examples where clearly it's a different style like there's photorealism and then there's this cartoony stuff well for one thing in most of these movies most of disney movies pixar movies there are photo realistic elements the hair the clothing things like that that you often don't notice like for example if you compare the first pixar you know the toy story one to the one that was made 15 years later you can see that it's not like they didn't they weren't after realism it's just that it wasn't available at the time so they are definitely making use of the technology as it's there in fact pixar is actually the developer of some of the great realistic technology that we that we have today in cg particularly the material stuff in fact if you look at the second latest pixar movie inside out which is arguably their most abstract cartoonish movie ever like taken inside someone's head it's full of photo realism like if you look around the scenes there's all sorts of realistic materials in there so it's not like it's not there it's often just not as obvious and of course their biggest example is their latest film uh the good dinosaur uh which some of the scenes could almost fit into a live action scene um they're so realistic the other thing is that um a lot of artists when they they look at a movie like disney or pixar you know with these really exaggerated stylized characters they think like oh that's what i want to do and i'm going to go straight for that when in actual fact you can't start at stylize you can't start at this exaggerated form without first knowing what the real form looks like because if you don't if you do that it looks wrong like you don't know which parts to pull and which parts to hold back excuse me that sound is my cat jumping up on the window so you have to know this in order to create a realistic um look in fact if you look at like most uh artists that work at disney they often have lots of realistic work in their background this is an example by the way this is uh some cartoonish work by jin kim but that they have that behind them and then they know how to when they come to the stylized art form know which parts to pull and which parts not to because it is actually a very delicate process it's it's not something like it seems easy like stylized like yeah i get to just make the eyes bigger and whatever but trust me i've tried it it looks weird it's actually really really hard to do so we often think of it like this like oh like uh there's two different fields there's realistic and then there's stylized when in actual fact it's more like this in order to get to the stylized thing you have to first be able to achieve the realism and that's pretty much true for everybody that works in that industry they won't they wouldn't be where they are if they didn't know how to do the realistic stuff first it really really is important so essentially it means everybody has to go through the realistic stage now we've got to move on uh to photo realism but if you're interested in more discussion around you know cartoonish versus photo realism uh click the link at the bottom there this guy talks about it in a little bit more detail and it uh really does make a lot of sense so that was the why why photorealism is important and i'm hoping that you would agree with me that it is definitely something that we should all be trying to achieve now we're going to be talking about the how the most important question how okay we're convinced how do you actually create something that is photorealistic so let's start with the most important concept the four building blocks of photorealism every photorealistic image out there has these four building blocks and they are best imagined as a house at the bottom of the house you have the modeling which is the foundation then you have the materials holding up a lot of the weight at the top you have the lighting again holding up a lot of weight and then at the top you've got the roof which is the post-processing camera work which is that final little layer of icing on the top some images will use more or less of another depending on what it is you're making and we'll show some examples overall but overall this is generally what it is and those two categories in the middle there the materials and lighting um they're big for a reason that's often where a lot of your effort goes in your image for example this quote by alex roman he reckons that 90 of the time the materials and lighting carry the weight of creating truly photo realistic imagery and from my experience working uh making the trailer and the product for the architecture academy um i really do think that's true that like you can get away with some you know cheating stuff in the modeling and you can kind of neglect the post-processing stage but you really can't go relaxed on the materials or the lighting so a couple of examples um this was a scene that we did for the prolighting skies trailer um but yeah most of the effort in this went into the materials and lighting like the modeling if say the railing was a little bit high or a little bit too you know short than it should be like you might slightly notice it but it's not that big of a deal however if the water doesn't look exactly the way water looks in real life the way it shades and reflects off the water you're gonna notice that if the lighting doesn't look like real daylight your eye is very good at picking that out there's a little bit of post-processing in here adding in some glow and other things like that we'll go into the detail by the way on all these i'm just giving you the overview at the start but yeah most the majority here is the material and lighting this example here by cornelius a lot more effort into the modeling mostly because there is a human character in it different you know rubbish things and you've got some scale um things that you have to adhere to but again most of the effort there is in the materials like it's basically a texturing demo it's really phenomenal and then a bit with the lighting as well when it comes to photo realistic characters um often you have to put a lot more effort into the modeling as well because um yeah it's we're really good at detecting flaws in the human face like one slightly like the cheekbones or cheekbones are a little bit too high and just the whole thing just just goes terrible so yeah it looking at this going cycling through it you can see that some depending on your subject you might end up doing a little bit more work in one than you normally would but as a general rule the materials and the lighting do make up a huge portion of it so those are the four building blocks and we're going to be discussing each four in detail right now starting with the modeling so i'll give you an overview of what each of them are you know like the general gist of what you know what is modeling what is photorealistic modeling and then some simple tips um in how you can yeah how you can make better models uh for more photorealistic results didn't explain that very well let's get into it so photorealistic modeling is matching the proportions and form of the real world object pretty basic it's the foundation for the image it's why in that that house example it's at the bottom of the building it's the foundation like it might seem like a small part and often times like you know the foundation's fairly easy get that down uh but if it's done wrong the rest of it just turns to crap so if it if you've if you've set up that modeling right at the start it means that the rest of the image is now good to go and you've got a good chance of getting it looking photo realistic so here are some modeling tips in order to create more photorealistic images so the first tip is one that i learned really late i wish i learned this earlier and that's to keep everything to a real world scale so blend is really good because it allows you to work creatively like if you want to just you know scale up an object you hit s and you scale it up unlike autocad or whatever you have to set you know each separate measurement for every corner or whatever so blend is really good it's a very creative tool but it also means that if you're not careful you can get into hot water because you end up just scaling things or moving and sizing things just by eye and your eye is very inaccurate uh we think we're accurate like i know how big a doorway is it's this size i know what a couch you know how big a couch is but we're really bad like the human eye is just bad at it because we give more emphasis to things that we pay attention to it's why when you ask someone to draw a face they draw really big eyes a mouth a nose and they forget where the ears are where the back of the head is and all that kind of thing we we put more emphasis on things that we pay attention to so it's not good so it says and then what that means is like say you're creating a scene and you're just doing it by eye like an interior um you'll get to the end and you're doing renderings you've done all the materials the lighting and all that kind of stuff and it just looks off like you can tell it's not photorealistic but you're not sure why it's like something something's not quite right about it i'm not sure and you end up fiddling around with the materials or the lighting and maybe those are perfect but the problem is that the foundation was wrong so this is what you do in blender make sure you're using some real world units i like to use metric really welcome to use whatever you want then i like to look up the real world height so if i'm making an interior room i just type in like average ceiling height or if it's got a person i'd say like average human height and often google will just tell you the uh the measurement like right there on the on the page and then i just go into blender and i just type in the measurement with the object selected of course and then even if you just do that for a few objects i'd recommend doing it for everything because really honestly it does help but even just a few objects you'll find that you get like the base like scale of the scene down and and by the way you'll be surprised how often you get the scale wrong like eyeballing things like you think yeah like i know the door knob height is about here it's not it's way off so just look up the average height of things and it's just it's it's an extra step but it means that later on you've got the right foundations and it's got a better chance of looking photo realistic tip number two in the real world there is no such thing as a sharp edge physically impossible a 90 degree edge anything like that it just does not exist and the reason for that is that like think of like the most sharpest object you can think of like a razor if you went in like microscopic level like it's still got some slight curvature and smoothness to that edge um it just couldn't exist there's no there's no way that a 90 degree angle could exist in the real world however in cg we get that by default when you add a cube it comes with these jarring 90 degree angles which is a physical impossibility so that's why this one is a simple easy tip that you can use just straight away and that's to use the bevel tool to round those corners now i've exaggerated it for uh for this you know demonstration but generally just give a really slight little edge to it and it might not seem like it'll do much in the viewport but when you go to render it you'll find that that edge it catches light it catches the reflections of the scene and it just gives it this slight little extra thing which just makes it feel a little bit more realistic so very simple but it does add up tip number three for modeling use the real world reference you know you can use photos but nothing beats the real thing so i mean using reference this applies to everything we're talking about modeling in particular right now but everything so when it comes to the materials or the lighting use reference as much as as you can but particularly with the modeling i find that when you're modeling something there's not enough photos online uh to complete most models like when i was doing this jerry can render um i didn't have a jerrycan this photo was taken later for this demonstration um so i had to go off photos online and there's just photos that you can't find like you'd think like google has everything but actually it didn't um so i couldn't find photos of the handle i don't know what this part up here looks like which is why it looks pretty dodgy um and so that's why having the physical thing really helps it's why a lot of like cg sites that have like textures and things they'll give away reference packs so that you can model say a car um and they give you like a collection of 200 photos because it's got photos of things that most people would never photograph like the door hinge um you know the the tail pipe bevel or you know things that just yeah nobody would ever photograph so you can spend way too long online looking for reference like come on where's that photo where's that photo when if you had the real thing available um it's it's going to allow you to get in really close and just view it from angles which is going to help you as an artist so i can't stress this enough it's a lesson that i've learned again pretty late but it's that yeah finding the real thing it makes a big difference it's why um like for every pixar movie if you look at like the making of they always send their team to like wherever it is so like for ratatouille they sent their whole or you know parts of their team to paris uh when they were shooting uh finding nemo they sent them to australia to do some scuba diving uh because real world reference is just so key you pick up things that you would never pick up otherwise so if you can get the real world thing get a hold of it if you're making a spaceship obviously you can't unless you live in area 51 um but you can get a hold of something similar so maybe like a military equipment maybe uh you know something similar to that thing but get in close to it and and get some get the real world reference all right tip number four this one is more applicable for um if you're doing characters but knowing your anatomy is just so important really ridiculously important if you're making a character um because we think we know you know you know if you look at a you know photo reference or whatever like oh that's where the cheek is that's where the uh you know the nose starts or whatever uh but we frequently get it wrong like the face it's something it's an area where you need to put special attention in and if you don't know the anatomy which is the underlying the bone structure where the muscles are where the fat pockets are where the different tendons are what attributes to aging what doesn't um like makeup for example is horrible if you're trying to reference a photo with the girls wearing makeup it's dead in the water already because makeup is all about faking like where your bones are and like moving this muscle up there or whatever just completely bonkers so knowing the anatomy is crucial when it comes to faces like i haven't done a cg face myself like a cg model of a cg modeled face for years um but recently i decided to do a drawing challenge so i just tried to figure out if i could learn how to draw um and at the start i learned i did a four-week facial anatomy course by scott eaton really boring i mean horrendously like some of the most boring stuff is anatomy it's just yeah but learning that um allowed me to it helped me out a lot later on um to the point that i would say if you are trying if you want to become a character artist one day um if you spent a year just learning anatomy that's probably the most valuable thing you could do for that year it's just so crucial and so many people that i mean some people even in the industry um are making you know characters and faces and things that are off they're actually wrong they're putting a wrinkle where they could not possibly be a wrinkle the eyes are just slightly too close together um and it's it's just crucial so know your anatomy and this applies you know obviously it applies to humans but also things like cars you know the forms and that's why again having the real world reference helps because you can hold it in your hands anyway we've got to move on so that's that's the basics of modeling keep it in real world scale never a sharp edge use reference and know your anatomy there's obviously a lot more you could talk about with modeling and go into the topology and all that kind of stuff but that is just way too in-depth and that'll be have to be for a different video um but anyway this is the basics when it comes to photorealistic modeling let me get another drink here materials so photorealistic materials are when the shading and textures matches real world materials so again looking back at our you know example here of what makes up photorealistic imagery materials are one of the biggest parts um so if you spent i don't know if you only had four hours to spend on an image to try and make it photorealistic you'd probably want to put at least two to 2.5 of those hours into the materials because you know modeling there's a lot of things that your eye can sort of get like provided you've got the scale and things right like you can forgive a lot of things like the eye can go like yeah you know it's a car but the materials there's something about you know the way that the light hits an object the way it's received into the object that our eyes just pick up on if the shading isn't just right if the texture is a slightly different way it's just going to look a little bit off so the eye is very good at picking up problems with materials so that's why this this step is really important so the first tip to recommend when it comes to making a photorealistic material is use physically accurate shaders so if you are one of the lucky few who gets to use an unbiased render renderer like octane arnold maxwell uh there's several others um then you have physically accurate shaders just automatically it just comes with it you create a shader or whatever it's physically accurate you don't have to worry about it if you like the rest of us and use something like cycles it's actually not physically accurate it looks realistic don't get me wrong but there's things that uh like for example this this shader on the left here compared to the one on the right the one on the left here is how i have done a shiny object probably ah what 10 11 years i only just learned this like three or four months ago basically that you don't just make you know to make a plastic material for example you don't just add a gloss and mix it with a diffuse shader like that's how i've always done in every tutorial like that that'll get you there like it's all right but if you want something that's photorealistic you have to take fresnel into account and how the fresnel is affected by the roughness of the gloss uh great thanks for that reminder um so you that's why um you have to you have to tweak it you have to go to the note editor you have to add these different things now i'm going to do a full video of this um either next week or the week after in fact if you've watched this at a later time you can probably just click the tip at the top there and that will take you through to the page uh sorry to the video but it's crucially important if you want to make a photo realistic material it has to actually behave the way real materials do and unfortunately most renderers cycles including one of them doesn't work by default not to say you can't get there i'm not saying like oh you should all switch to arnold or whatever because you pay for that with increased render times or whatever but you just have to be aware of it and know that you have to tweak it in order to get a realistic looking shader but again we'll go into that in a future video the next thing is in relation to um the variance of materials so take for example an asphalt road um like if you're standing over it looks like the one on the left there but when the light hits it at an angle you can see that um it's not just like a you know a diffused looking material with bumps on it it's got little parts in it with different amounts of reflection some parts are like a sharper reflection than others um and this other example of this photo i took whilst uh driving it was really early in the morning it was a back road nobody was there and i was like look at that road so i took a photo of it uh but you could see like uh you wouldn't see this if you were standing over it but at an angle you could see that where cars have driven along it it's like melted the bitumen and it's become like this smoothed area so uh we think and and i was eating a magnum ice cream the other day on my cheat day and uh and i was like ah look at that even the magnum ice cream it's got a whole bunch of variants on it so when we're making things um in cg like you know like this example here it's like oh this is plastic i'll just make it this shiny plastic but actually in the real world there is variance across every material property this variance across like the sharpness of the reflection there's variance in which parts are more reflective than others and there's variance in the color like you look at this magnum ice cream like that's just a solid brown but if you took it under a microscope and like looked at it some parts are darker than others some parts are like more translucent um there's parts the especially the reflection of course you can see like when i peeled off the wrapper it's got like parts that was stuck to it you know little icicles and little tiny bits like that but in you know in cg adding that stuff it's like oh man like that's this is fine it's a table you know it's or it's a countertop it's a reflective countertop so be it but real life there's always variance even if you had like a mirror like this is a mirror it's a chrome mirror it's reflective right not so i'm sure if you took a mirror and like examine the properties i'm sure even there there's like variances in the reflection so essentially you should never have just the default um diffuse never have the default gloss anything like that there should always be some variants to it and that is why i recommend using pbr maps now if you haven't watched my video on polygon uh you can click this center thing right here that'll take you there so you can check it out but we talk about this in detail essentially when you take um an image texture and you just put that into 3d software the software doesn't know how to treat the material so it just basically treats it like you'd printed out you know the the the texture on a piece of photo cardboard or whatever it doesn't know where the bumps are or where there's more reflection or less just treats it like that our pbr maps are separate images that go with that image texture and they let the software know where the bumps are where there's more reflection where there's less etc and when used in combination the results are night and day you truly get results that just it just looks way more photorealistic so that is why we created polygon polygon.com i'm going to plug my own website here why not um so we create a polygon because creating these maps takes forever so we made polygon and basically that offers all of these maps for you which allows you which allows that very thing what we're talking about material variants you get that built into the material so you just download the maps you put them into blender which i'll show you in the next video of course and that allows you to get pbr maps if you want you can generate your own maps yourself using software like nald or crazy bump or any of the other ones out there but polygon is the easier route the next thing next thing to talk about very similar to the um you know the fact that all materials are varied is surface imperfections um so this is something that again you probably don't notice it that much in life but every surface in the real world has some form of imperfection to it the only way i could imagine one that doesn't have it is if on its creation the material was put into a black vacuum that was not exposed to any of the real world properties then it would have no surface in effect but anything in the real world it's got some level of dust it's got a little bit of dirt maybe it's got some sun fading from being in the sun too much subtle again really subtle but everything has it even things that you think are clean if you look at it at just the right angle that counter top that looks uh sparkly clean it's got tiny little bits of dust on it or it's got like the residue marks from when you're wiping it with a cloth everything has this fine amount of surface imperfection so again to plug polygon that's why we created surface imperfections known as overlays um so overlays look like this and they're maps they're things that you fo you come across in the real world um to replicate and put on your objects so smudges scratches dust uh residue all sorts of different things like that so this is what's going to allow you to get that next level um photo realism it's something that most artists just don't bother with like you know they make a phone in cds like hey i finished the phone and you know that you know a real phone's got fingerprints all over it um but where do you find a texture like that so anyways you can take it or leave it it's on polygon if you would like it if you would like it but we have maps for that as well so that is the materials use physically accurate shaders use pbr maps and use surface imperfections that is what's going to allow you to create a photorealistic material let me get another drink here lighting so lighting is again in similar ways to the materials is quite important it does hold up a lot of the weight of making that final photo realistic result so important photo realistic lighting is light that matches the color direction and intensity that you see in real life so sounds simple and in a lot of ways actually lighting is quite simple especially when we get to the end i'll share with you a cheat but the first one is the light direction and this was one that i learned pretty late as well um i remember when i was for this tutorial here um i was trying to put together this scene it was like i think my first interior render that i'd done before um and what i had was i had a reference photo that looks very similar to this and i wanted to try and create it so i had a window plane on the right hand side this uh this plane right here oh look at that you can see my cursor um so i had that and um so i had a uh i was gonna try and draw with it but i had a plane and i figured like okay the light is streaming in through this window here so i'm just gonna have a plane i'm just gonna make it 90 degrees facing this way like this like into the room um and so i just rotate it 90 degrees pointed like that and every time i rendered it it just looked off looked a little bit like something wasn't right it didn't look like the real world light and then i finally like all right forget it well then i'll just i'll make it i'll rotate it like it is in the real world after trying so many things and it just immediately looked way better so instead of it being like rotated top like vertically like this i made it horizontal and then i added over here like a separate plane to act as like the ground bounce light excuse me the ground bounce lighting um and instantly just looks so much better and the reason for that is that light has a number of properties that we we don't really notice with our human eye like like fall off like light from the sky or any anywhere it falls off with uh with distance and having the light you know like oh i'm just gonna throw a light here and just you know like that um it misses that fall and also it's just um the way light and shadows fall in real life it's again it's something that we just don't notice with the human eye so i find it best no matter what it is you're creating just imitate the real sky imitate where the light actually is even if it's off camera and you've just got a character that's standing in a room or whatever it's like i don't need to bother with a a window i'll just put this lamp just over there that's going to be as if the the sunlight was streaming through a window no i highly recommend actually going to the trouble of modeling a window that you can't see so the light can stream through it it's subtle and in some ways i can't really explain why it just looks so different but it does it's just i think light is one of those things where you you don't notice the differences until it's wrong um and so the quickest way to do that is just i mean basically at all times the light has to come from up above that's just we live in the real world where the sun is above us pointing down um and so you have to be pointing down um and yeah just yeah if it's an indoor scene imitate where the light's coming through a window all right next up is the color um so this is one that is um it's simple simple tip um but it'll make a huge difference in your final image and that is to use the real correct world color and essentially real light in the real world so light from the sky or light from the sun or light from fire or even light from old style bulbs like incandescent's halogens they all fall into the kelvin scale so if you just go on to google and just type in kelvin scale you'll find a graph like this but essentially it's it's a it's a measurement that's based on temperature and it defines like how light looks at different temperatures and the color it has um so you can see it all fits in there everything from you know the sky to yeah artificial light um leds and lights with filters you know obviously you can put a purple filter over a spotlight in the real world and you can get purple light but generally if you're going for a natural look um if you just you know stick to this black body temperature thing which as you can see in the bottom right hand corner that's how you can do it in blender you just add the black body node and then just set the temperature in there um i think like 95 of the time for most scenes this is good enough like you don't really need to use much else than that i highly recommend using this over like just picking a color like oh i know what color and a sunset is it's a it's an orange sun like we think we know we think we know what color it is and then you render it and it's just everyone else is like that looks way too orange you know so stick to the black body um uh temperature node and it's going to look a lot nicer i mentioned in like the previous uh character lighting video um that this is especially true yeah if you're trying to go for a natural sort of look you know photo realism but you know other colors still have their play if you're trying to go for a surreal or like urban sort of look like you can get away with different color usage but yeah like i said 95 of the time this is going to be uh the way to get there next up is tip number three don't forget the reflections so a lot of times the reflection is often just as important as the actual light um because if you're modeling say if you're rendering something like a car like a car is very extremely reflective and if you've just got a lamp pointing at it like it's actually not going to affect it if you increase the sun lamp or increase the lamp or whatever the only thing that's going to matter is the reflections and in 3d we're often we think about what's in front of the camera we don't think about what's behind the camera but your objects will and every object has some amount of reflectivity to it so that's why your scene needs to have reflections to it like the sky for example needs to be present um so that your objects can actually reflect that sky so as if you've been following blending guru videos for a while you probably know that i'm a big fan of hdr environment lights so hdrs are 360 degree photos which can power the light of your scene so it actually does all these things that i've mentioned in one go so instead of needing to set up the correct light direction set the correct temperature and then trying to figure out how to do the reflections for that you just add in one hdr and you don't need to add any lights to your scene it does the reflections does the correct direction and the correct color and the correct intensity so hdrs are just brilliant so it's one of those technologies which has just made cg life way easier and uh and it's brilliant now i wish i had a uh like a pack of hdrs that i could recommend oh i forgot uh pro lighting skies so that's why we made pro lighting skies um it's a pack of 80 hdrs which if you're interested in you can click on this link here and that'll take you through to the page but essentially for blender users it's um it's the easiest way to get hdl lighting inside blender so it's there if you would like it otherwise you can go and download any other number of hdr packs online it is up to you so that's lighting use the real world direction very important ensure you've got the correct color using a black body temperature node and basically use hdrs if possible or some other method to get reflections because they are just as important as the lighting last on the list is post processing so in terms of everything else the modeling the materials the lighting post-processing is fairly easy easy to an extent because it's fairly predictable the whole point of post-processing is uh to recreate the imperfections that you get from real life cameras because a camera in real life has a whole bunch of imperfections the photographers hate and they're constantly battling against but they are present in everything that's captured with the wheel with with a real world camera but in cg we've got a digital camera that comes out with perfectly clean perfectly crisp perfectly perfect images which is a physical impossibility it just does not exist in the real world so that's what this step is all about it's bringing some of those imperfections into your renders so that it looks more like a photo um i love this quote from bench bertrand benoit from the architecture academy he said i think very strongly that one should come to cg as one does to photography you can have perfect technical mastery and still fail um if you frame compose or light your shot in a poor way this is why if you actually if you look at some of the best cg artists today i mean you look at their work they've often got a strong passion for photography it's a hobby or it's something that they dabble in to you know increase their skills because that's like that's what we're doing cg artists we're recreating a photo and if you don't know how cameras really work you're going to be disadvantaged as opposed to somebody who does so that's if if you're looking for a hobby to have on the weekends or something to improve your cg work photography is for sure a really really good one i would say that mo like every cg artist needs to have at least some understanding of photography especially if you're trying to achieve photo realism um so if you can pick it up as a hobby even if you just get your iphone just like go outside and play with it or whatever you're still gonna get a better feel than somebody who's never picked up a camera before so give it a go um so there are five main imperfections five main camera imperfections which i think are the most important and they're the ones i'll address right now the first is light glare so this is of course most you know prevalent if you take a photo and it's got the sun in the background you get a lens flare or if you watch a jj abram movie i took it's old um but but lens flares they are they are um what they're gonna say they're in every photo whenever there is a bright light source against a something which is dark um there's going to be that that effect um and the cause of it from my understanding somebody correct me if i'm wrong but uh the light enters through the lens and due to the number of elements inside the lens like 18 elements or whatever it all bounces off these little elements um and it you know enters into the frame like that that's my understanding of it and in fact even the naked eye like if you squint like at a lamp source uh you'll find that you you see that as well and i've been told that's actually the light reflecting off your eyelashes i don't know either way light glare it's something that if you don't have it by default when you do your render it won't be there but thankfully it's quite easy to add in the compositor so if you're in the compositor you just add a glare node you want to make sure that you first of all isolate your light source the glare node has a way of reducing the threshold using that threshold value there so you can just plug in your render in there and then you know define your threshold like that i like to move my lamps onto a separate or give them a separate object index and put that object index to another object index node put that into the glare glaring and then you've actually got the real lamp sources themselves they just give it a little hit you just give it a little bit of glare it's subtle and it's it's not going to make that much of a difference but it's just when you look at a final render it doesn't have it it's so clear that it's cg so simple thing that'll make a big difference motion blur is very important as well and this is where i guess um i'm like everyone knows what motion blur is but having a knowledge of photography will help you know when to use it motion blur is most um most obvious in low lighting conditions because the shutter has to be open for longer my goodness you don't quit thank you toggle um it's most probable because the shutter has to stay open for longer um yeah to capture uh yeah to capture the light of the scene so that's why you get motion blur in low lighting scenes so when you're at a party with friends and it's like it's a birthday happy birthday and everyone pulls out their cameras and they all come out blurry um because there's low lighting and you just you can't focus um so the the the the shutter is open for longer and through the blurriness of your hand um it comes through so that means when you're making work if you've got a i don't know a car moving through the night it's speeding around the corner it's gonna be motion blur if you've got a spaceship that's going through space and it's very low light there's gonna be motion blur if it's bright daylight and there's a camera is being held by someone it's gonna be less motion blur but there should always be a tiny amount to the point that photographers actually go to crazy length to reduce their motion blur by using things like mirror lock up on the camera and a remote trigger so even their finger pushing the shutter even if the camera is on a tripod it's completely still even pushing the shutter with your finger will slightly move the camera which can create a slightly blurry looking image so photographers go to extreme lengths to make sure their camera that their image is tack sharp so again this can be used to um interesting effect like if you've got a scene and you want to make it look like it's taken down a dark alley way during a fight and there's somebody with a handheld camera there's going to be a lot of motion blur because there's no way you're going to get a completely crisp render so simple in blender now you just check a little box in the render panel there another really big one and really important is depth of field so most people probably already know about this but that is that in in photography only one thing can ever be in focus ever um so either the background is out of focus or the foreground is or a little bit of both focusing on the mill but there's no possible way that a that a shot can ever be 100 crisp in focus so basically what i'm saying is that depth of field should always be on in blender for any render that you do photographers wish they wish that a lens existed or a camera existed where they could possibly capture everything in crisp focus because landscape photographers love that they love the fact they love being able to um to one shot be able to capture the entire landscape from like you know naught to you know five kilometers in the distance but often even with the best lenses that enable an f-stop of like crazy high they have to take multiple camera shots um of different focal lengths and then in the computer compose them over together to try and get that ultra crisp sharp image and i'm saying all this because in blender or cg at all we get that by default which is not correct there's no possible way that a completely crisp perfect in focus thing could ever exist so you've got to add that really simple in blender you just go to the camera box panel thing there you can see it on the thing it's a screenshot you click depth of field and that little eyedropper tool there this little guy you just click that and then you click somewhere on your image you want to be in focus like this candle uh and then you set the f-stop to 5.6 that's the one i like to use it's the one most cameras use or whatever for like the most crisp shot i just leave it at 5.6 usually pretty fine for portraits and things like 3 to 5.6 is fine for city photography like 11 is good and then like landscapes it's like 24 or as high as you can go um but anyways those are some basic tips number four let me get another drink here always happens and i never do a video gotta take a drink chromatic aberration so this became it became a problem like five years ago i think when like one artist realized that hey if you add a little bit of chromatic aberration to your image it looks realistic and then everybody started abusing it i even included in my wow factor book and like i it it it can be abused really badly chromatic aberration is what you can see in this picture there um it's most apparent when you take a photo and it's got some trees in it the trees against the sky and you see that fringe that color blurry fringe it can often be like red or blue or this cyan color that is chromatic aberration and again it helps to know when it is used so it's something bright meeting something dark and it is most apparent in a cheap lens so this is really crucial because a lot of times you find artists that are adding the chromatic aberration because it's super easy to add as you can see there it's just a one node you add in the compositor they um they add it for like like say they got a scene and it's supposed to look like a professional um architecture scene like really crisp like really nice architecture they've got the lighting perfect everything is right and then they throw in chromatic aberration that doesn't make any sense because if this was a photo if this was like a professional setting with all that stuff set up and good to go there wouldn't be chromatic aberration because the architectural photographer would have gone to great lengths to prevent that they would have used a lens which was not really um which wasn't crappy because like chromatic aberration like this is like it's really apparent in like old point-and-shoot cameras those old pocket camera things um yeah so it you've got to know when to use it so if you're going for like a cheap lens camera thing or whatever a little bit of chromatic aberration use it subtly just a little bit and it's generally most apparent on the edges of the camera not in the center so fyi next up and last of all is the barrel distortion so the barrel distortion is that again it's one of those things that photographers hate and they're constantly trying to get rid of and it is that everything in that that's captured with a camera has a slight bend to it so look at this photo that i took in japan you can see that this is a completely straight wall here but if you look at these these are these these are the actual straight lines where the wall should be but due to the barrel distortion of the lens it has a slight bowing effect to it and the reason for that is that every lens is um slightly curved that's just how the lens works so everything has a slight little bend to it so actually if you take a photo in raw you bring it into photoshop you set the lens profile correctly it will get rid of the barrel distortion for you or at least you know its best attempt at it but it's basically just reversing the barrel distortion so again every photograph in the real world that has a little bit of barrel distortion that's why it's so important that's why you have to add it to your images if you're going for that look if you're going if you're going for a really like professional photographer look you wouldn't maybe have it because yeah you uh you would have removed it i guess if you're trying to go for an invitation like that um but yeah so and it's most apparent in uh wide angle lens shots as well it's i mean the most obvious example is a fisheye lens if you've ever watched a skate video um that it's it's like barrel extortion to the absolute extreme uh so yeah the more wider the shot the more barrel distortion you're gonna see so again it just helps to know when to use it but it's pretty simple to add in just a lens distortion node just again use it subtly really super subtly all right so there you go that is post processing slash camera it's adding glare motion blur depth of field chromatic aberration barrel distortion it's all the things that you get in a real camera that you need to add to your digital camera to make it a digitally perfect image so there are all the points again the modeling the materials the lighting and the post processing um if you followed that advice there they would get you probably 90 percent of the 95 99 of the way i don't know i'm just making stuff up um the rest of it the rest of photo realism is all about following reference and this is something that you'll get better at with time um in that at the start you might not be able to pull off photo realism and that's that's totally fine you might get really close and that's that's admirable like i still i mean every artist still struggles with it photorealism is the holy grail for a reason um but as you do it more and more and throughout life like those images that i took of like the materials like the ice cream and like the roads and things like that that's just stuff that i noticed in my life um because i suppose probably with the uh with creating polygons and things like that i'm particularly interested in texture and when you start doing things over and over you start to notice it more in life so when it comes to making you know your um i don't know your render of i don't know what's something people always do render of an iphone or something you'll be able to to look at a reference photo and be able to find things that most people would overlook the slight beveled edge with the little chips along it with the tiny little bit of dust that's caught in the microphone hole at the top there little tiny details that you wouldn't only notice it's something that you just pick up over time but that's basically it's reference and these simple tips right here so there you go go make some awesome renders um if you like this video please give it a thumbs up if you would like to see more videos like this one go ahead and click subscribe subscribe and uh if you'd like to see um some more interesting videos check out this video on understanding composition where we talk about how to create a visually interesting framed how to frame an image so that it's visually interesting um but anyways that's it for me guys thank you for watching see you next time

Channel: Blender Guru

Views: 1,536,632

Keywords: cg, cgi, photorealism, blender, tutorial

Id: R1-Ef54uTeU

Length: 53min 49sec (3229 seconds)

Published: Wed May 25 2016

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