WEBVTT 00:02.390 --> 00:08.000 Welcome to a physics based rendering or often shortened to just p.b. are. 00:08.510 --> 00:14.720 So this is all about chasing realism getting those materials as close to reality as possible. 00:14.720 --> 00:19.180 Now what we're talking about here is render time PBR rather than real time. 00:19.180 --> 00:25.180 PBR in the viewport So we'll be talking about what is necessary for creating anything realistic. 00:25.220 --> 00:32.090 When you go ahead and hit that F 12 key for a full time round or in fact if you've just got the viewport 00:32.150 --> 00:34.520 on rendered mode as well. 00:34.820 --> 00:41.060 We're going to get something looking like it does in the real world and that is critical for a lot of 00:41.060 --> 00:42.600 work now. 00:42.770 --> 00:46.850 When you focus on something that's physically based. 00:46.970 --> 00:54.890 We're talking about how objects really are in the real world cycles itself is almost there but it does 00:54.890 --> 00:56.530 miss a few points. 00:56.600 --> 00:59.970 So you can't expect it to do perfect thing straight away. 00:59.990 --> 01:02.170 You need to guide it along its way. 01:02.240 --> 01:10.130 It doesn't calculate for now automatically of certain materials unless you tell it to and roughness 01:10.130 --> 01:13.360 can be tweaked a little to make it a bit more usable. 01:13.360 --> 01:20.880 And I have a look at those two things shortly correct but not always right. 01:20.900 --> 01:28.550 Now this may sound a bit like an oxymoron but getting something physically accurate will mean it looks 01:28.550 --> 01:30.410 correct. 01:30.410 --> 01:36.140 It might mean however that it doesn't look right and that sounds like a very odd thing to say. 01:36.260 --> 01:42.680 But if you've got something a vision that you want to create it might not be possible to create it in 01:42.680 --> 01:44.320 the physical real world. 01:44.330 --> 01:46.380 I mean that's the great thing about CGI. 01:46.520 --> 01:53.510 And certainly if you or making a space ship they don't really exist at the moment or if you're making 01:53.510 --> 02:00.690 an alien so making something look physically correct might not be the impact you want to create. 02:00.830 --> 02:03.970 But it's a great starting point. 02:04.220 --> 02:10.850 One sure at this stage whether it's modelling to get it looking physically accurate or materials it's 02:10.850 --> 02:18.500 better to get to that stage first and then become more stylized rather than trying to jump to the stylized 02:18.860 --> 02:24.000 whether it's over overexaggerated jawlines or an annamay style. 02:24.020 --> 02:29.630 If you're talking about the modelling or whether you're talking about skin that glows or something along 02:29.630 --> 02:36.200 those lines it's better to have a realistic first and then become more stylized because you're starting 02:36.200 --> 02:38.060 from an accurate point. 02:39.380 --> 02:47.000 So what is done and when it is very important when you render something it comes out perfect every time 02:47.750 --> 02:51.060 the real world is not perfect. 02:51.170 --> 02:55.440 Our eyes camera lenses etc are not perfect. 02:55.450 --> 03:01.980 A small they have little imperfections in them which make well make life a little bit more interesting 03:02.210 --> 03:09.050 and that's why sometimes when you're really stretching for that extra bit of photorealism having some 03:09.140 --> 03:13.680 imperfections in the scene add a lot to it. 03:14.300 --> 03:23.470 Things like depth and field focus glare lens flare are all added after the scene has been rendered and 03:23.480 --> 03:26.430 this stage is called post production. 03:26.450 --> 03:28.780 Or sometimes post processing. 03:29.810 --> 03:33.220 Okay so what is wrong with roughness. 03:33.440 --> 03:41.000 Well there is a massive drop off in sharpness between a value of zero and zero point one and then it's 03:41.000 --> 03:49.220 much slower in terms of how it's changing after that so as not linear it drops off very quickly and 03:49.220 --> 03:56.690 being non-linear it makes it very difficult to use because a small adjustment low down is going to make 03:56.720 --> 03:59.300 a big difference. 03:59.300 --> 04:06.260 We aren't going to use the maths node to try and correct this and will go home to learn a couple of 04:06.260 --> 04:09.040 new node commands as well. 04:09.260 --> 04:12.360 Now before we go in do that we just want to see here. 04:12.380 --> 04:21.380 Default vs. adjusted so we have a ball a sphere that's in an environmental texture which is the photo 04:21.380 --> 04:28.880 I have taken and we can see that with the roughness values the jump between 0 and 1 is quite extreme 04:29.180 --> 04:36.390 but as we go along to just point five we can see that it changes very slowly. 04:36.710 --> 04:44.330 Now using the maths node we can see a just how those values account collated with the slider and we 04:44.330 --> 04:46.690 get a complete different effect. 04:46.700 --> 04:50.350 And this is going to make it much easier to control and not. 04:50.360 --> 04:53.010 You don't have to just apply this to roughness of course. 04:53.090 --> 04:58.640 We're just using this as an example of how we can manipulate how something is working with something 04:58.640 --> 05:00.770 like a maths node. 05:00.860 --> 05:05.710 So let's go explore the maths node now and hop on over into a blender. 05:06.020 --> 05:07.760 Okay so now we're over in blender. 05:07.760 --> 05:13.050 I'm not gonna do this with a keyboard could do with a Q but I know I'm going to do a sphere. 05:13.070 --> 05:14.890 Spheres look better in cubes. 05:14.930 --> 05:17.450 Don't obsess Cubists a space. 05:17.480 --> 05:18.160 So there we go. 05:18.170 --> 05:20.460 Let's add a newbie sorry I'm going to make it smooth. 05:20.480 --> 05:27.050 I'm also going to go to the subdivision's surface modifier and under the render settings just turn that 05:27.050 --> 05:28.930 up to six. 05:29.090 --> 05:33.410 Then it's going to be super smooth and want to look and have any horrible artefacts when it comes to 05:33.410 --> 05:34.110 rendering. 05:34.540 --> 05:42.320 I will add a material to its already and I'm going to set it to be a glossy shade up that's fine so 05:42.320 --> 05:46.170 the only other thing were missing is if we hop over into rendered mode. 05:46.190 --> 05:47.720 We don't really get much. 05:47.720 --> 05:51.580 We get a grey ball because it's reflate in the grey environment. 05:51.590 --> 05:54.590 So let's go ahead into the world tab. 05:54.590 --> 05:57.470 Use nodes and of colour options. 05:57.470 --> 06:02.140 I'm going to click the little dot to the right load in an environmental texture. 06:02.140 --> 06:07.530 Now this isn't actually an environmental texture of I'm going to load in as such is just a picture of 06:07.530 --> 06:08.610 I've taken. 06:08.870 --> 06:13.610 If you've got other textures that you want to load em by all means do that. 06:13.610 --> 06:15.840 Otherwise go to U.S. assets. 06:15.910 --> 06:19.220 You should find two panoramas that you can pick from. 06:19.220 --> 06:26.690 I'm going to pick this one here and I'm going to whiz over to the camera feed to see which view we've 06:26.720 --> 06:28.610 got cayla. 06:28.670 --> 06:34.100 So now they're really like that song going to go into first person moving mode. 06:34.130 --> 06:38.930 Now you can see here this isn't a perfect wraparound text or anything like that is little she just panorama 06:39.050 --> 06:39.730 taken. 06:40.040 --> 06:42.720 So the world has ended there and started again. 06:43.830 --> 06:51.070 So we want to be able to see some mountains and I quite like the look of that. 06:51.900 --> 06:55.650 And then a heif 12 quickly just to see how that renders out. 06:55.920 --> 06:59.070 Again this is important that you check your work often. 06:59.160 --> 07:06.280 That looks absolutely fine to me now because it's lovely and smooth because of the six subdivisions. 07:06.330 --> 07:08.990 We get a nice crisp border going round. 07:09.180 --> 07:10.680 Okay so now we've got that. 07:10.680 --> 07:15.220 Let's change this little box this outline up top. 07:15.220 --> 07:17.520 Well I'm going to remove the lamp for a start. 07:17.520 --> 07:22.890 I'm going to delete that from our scene completely and go change this to the 3D view and change it to 07:22.890 --> 07:25.260 rended mode and view it from the camera. 07:25.500 --> 07:30.480 So we get an idea of what's going on life now that we've done that there's an awful lot of black in 07:30.480 --> 07:32.670 the scene so the know how that's going to pan out. 07:32.670 --> 07:35.330 Hopefully not too bad but now we've got this. 07:35.330 --> 07:42.210 In the scene we can switch this big area over to the node editor and trust me to get rid of the outliner 07:42.240 --> 07:46.770 when I don't think we've actually got this sphere selected someone to go back to 3D view select the 07:46.770 --> 07:47.730 sphere. 07:47.730 --> 07:52.710 Now we've got it selected when we go to the node of to the node setup will be there. 07:52.920 --> 07:57.880 Okay so there's a couple of things that we're going to have to add to our node setup. 07:58.020 --> 08:04.020 One is a maths node and that can be found on the menu and go down to. 08:06.290 --> 08:10.800 Converter maths and we'll plot that. 08:11.150 --> 08:14.740 And that's the value output is going to go into the roughnecks. 08:14.750 --> 08:16.350 That's what controlling. 08:16.490 --> 08:22.820 Of course we lose the ability to control the roughness here because it's now being controlled by this 08:22.850 --> 08:29.510 node we can change the type here so we can do loads of different options. 08:29.510 --> 08:36.110 And the final thing that we need to do is have a way of controlling these values here. 08:36.590 --> 08:45.610 So I'm going to add in another node a very useful node is in inputs because it's giving input I suppose 08:45.620 --> 08:49.570 nice and straightforward and it's just value is a slider. 08:49.730 --> 08:52.540 And from things like this we can join the. 08:52.550 --> 08:59.420 It's to both of these for instance and then control them both at the same time now at the moment. 08:59.450 --> 09:02.100 We can see if I said that point one. 09:02.210 --> 09:05.380 It goes all fuzzy so that's not quite right. 09:05.420 --> 09:10.850 I think we need to play around with this maths though and find the right selection of what's grouser 09:10.850 --> 09:16.490 we're adding here so this is going to add point one to point five. 09:16.490 --> 09:21.770 And what we want to do is I'm going to link these back up against us almost as if this is not here. 09:21.770 --> 09:28.340 Incidentally you can also do that by hits selecting it and hit me M key for mute. 09:28.340 --> 09:32.230 Ill undo that all together and then we're literally bypassing it. 09:32.230 --> 09:35.330 And this value is now controlling the roughness directly. 09:35.360 --> 09:39.400 So we want really the value here. 09:39.410 --> 09:43.750 By the time you've gone up to point five it's pretty obscure We can see. 09:44.060 --> 09:47.760 So to get an actual reflection we're doing things like oh point. 09:47.810 --> 09:52.220 1 and No points nauts to an open or three etc.. 09:52.370 --> 09:56.180 Quite low value is where would be quite nice to be able to have them higher up. 09:56.300 --> 10:01.090 So whatever we do with the maths node has got to lower this value. 10:02.260 --> 10:05.250 And with that comes a challenge. 10:05.500 --> 10:09.300 I would like you to go ahead and smooth the roughness. 10:09.730 --> 10:12.910 Play with the maths node and its options. 10:12.910 --> 10:19.180 Can you figure out a way of smoothing the sudden change where one moment the image is reflective and 10:19.180 --> 10:21.770 then all of a sudden blurred out. 10:22.730 --> 10:27.830 There is no right answer here because there are going to be a couple of solutions that work for what 10:27.830 --> 10:35.930 we want to do play with it think carefully if you if you combine numbers how do you get a lower number. 10:35.930 --> 10:37.190 Think about it. 10:37.430 --> 10:40.400 And please do remember to save your results. 10:40.400 --> 10:46.480 We aren't going to use it again shortly possibly an hour and give that a go. 10:49.360 --> 10:50.120 Okay guys. 10:50.140 --> 10:51.350 Welcome back. 10:51.400 --> 10:55.100 Let's go smooth out the rough ness and play with that maths note. 10:56.870 --> 10:58.580 Okay so back over him blend. 10:58.580 --> 11:01.400 I'm going to unmuted the maths node. 11:01.620 --> 11:02.340 Okay. 11:02.360 --> 11:07.270 So if we how do we get lower values we can subtract. 11:07.330 --> 11:09.390 McKay what happens if we do that so. 11:09.500 --> 11:10.850 Is there a subtracts. 11:10.850 --> 11:13.850 Yes there is a subtract and. 11:14.850 --> 11:20.940 Subtract the value of that's going to clampett low so it's going to be zero essentially cause you can't 11:20.940 --> 11:23.340 get less than zero with the roughness. 11:23.340 --> 11:27.740 So it doesn't matter what this number is when it goes to point five. 11:27.740 --> 11:35.160 It'll then be zero and then so that's just offsetting the problem that's not going to solve that's all 11:35.160 --> 11:36.560 multiplying. 11:36.610 --> 11:37.670 Mm okay. 11:37.710 --> 11:41.710 So if we multiply it by itself. 11:42.850 --> 11:48.260 So point 1 if you Times point by point 1 you get point nought one. 11:48.300 --> 11:50.190 Now that's lower the value. 11:50.530 --> 11:52.620 Okay let's see what happens then. 11:52.630 --> 11:53.590 So we go to a point. 11:53.650 --> 11:56.600 One are but looking a bit better. 11:57.830 --> 11:59.940 I presume as we step up. 12:01.060 --> 12:03.870 Yes that's looking much better. 12:03.880 --> 12:04.540 So there we go. 12:04.540 --> 12:06.420 There is one option. 12:06.430 --> 12:07.820 We can multiply. 12:07.960 --> 12:13.780 But that does give us not quite the flexibility I would like. 12:13.780 --> 12:19.660 That does give us the a right answer in this case but there's something else we can do here as well. 12:19.660 --> 12:23.240 So let's have a look at some other options. 12:23.710 --> 12:24.840 Power. 12:25.150 --> 12:32.180 So what we've done here by timing it by itself so point one times point 1 we've squared it so that's 12:32.230 --> 12:34.140 the power of tippoo. 12:34.240 --> 12:40.870 So if we go ahead and change this to power and we don't want it to the power of its self because it'll 12:40.870 --> 12:43.780 get tiny butts. 12:43.780 --> 12:51.920 If we set the value here to two we've got point one to the power of two and then it comes out here. 12:52.740 --> 12:55.620 Oh case let's just test that again sir. 12:55.620 --> 12:57.640 Point One Point Two. 12:58.400 --> 12:59.840 Point Three. 13:00.080 --> 13:00.800 Excellent. 13:00.800 --> 13:03.240 That is working of course one. 13:03.260 --> 13:06.630 So the power of two is still one. 13:06.740 --> 13:13.940 In fact one to the power of anything is still one see you do get the hundred percent roughness as well. 13:13.940 --> 13:15.330 If we go all the way up. 13:15.410 --> 13:17.620 Of course one times one if you've got the power there. 13:17.690 --> 13:21.680 So this gives us the other option of increasing this so we could do to the power of five. 13:21.680 --> 13:24.100 Now I'm not quite sure what that's going to do. 13:24.260 --> 13:29.670 Let's have a quick look at what a hold down Shift here so I can Mike remove this as we go across and 13:29.870 --> 13:34.360 we can see that it really starts getting blurry much later on. 13:34.440 --> 13:42.040 And this gives us much more fine control over those reflections or rather the roughness of that surface. 13:42.080 --> 13:48.590 I think five is a little too high because that's going to start making it difficult the other way where 13:48.590 --> 13:52.730 you can't really get it's where it's bunched up. 13:52.730 --> 13:54.850 The other end if we do that. 13:55.110 --> 14:02.320 So right after experimenting ifes I'm kind of settled if we go to point to here and we can compare it 14:02.330 --> 14:04.430 bourges muting this. 14:04.610 --> 14:05.160 No. 14:05.180 --> 14:08.470 This power node here we can have a look in the top there. 14:08.630 --> 14:12.970 And when we mutate we consumed it was like all it now is like. 14:13.000 --> 14:15.490 So 2.5. 14:15.830 --> 14:17.940 And we can go backwards and forwards. 14:17.990 --> 14:22.620 I think a value somewhere between two and three works out really well. 14:23.500 --> 14:25.720 Remember to show your work in the discussions. 14:25.720 --> 14:29.040 Did you come up with a similar node setup to this. 14:29.140 --> 14:35.680 If so brilliant if you came up with something different I'd love to hear your thinking how you worked 14:35.710 --> 14:38.910 out how to teach maths know to use. 14:38.930 --> 14:41.170 Did you approach it from a completely different way. 14:41.170 --> 14:43.950 I've tried to talk through roughly my thinking there. 14:43.950 --> 14:49.330 Obviously I've been playing with it for a while so I've got some preconceived ideas of what was going 14:49.330 --> 14:49.480 on. 14:49.480 --> 14:50.800 But if you're completely new to this. 14:50.800 --> 14:58.330 I'd love to hear your thought process on how you came about completing this challenge. 14:58.330 --> 15:01.470 And as always I will see you guys in the next lecture.