WEBVTT 00:00.980 --> 00:03.980 Welcome to subsurface scattering. 00:04.190 --> 00:06.800 Now what is subsurface scattering. 00:06.800 --> 00:13.640 Well it's a node that was recently introduced into a blender that allows us to mimic a certain affect 00:13.700 --> 00:16.220 of indirect lighting. 00:16.220 --> 00:21.200 So long it would penetrate a surface of an object in real life. 00:21.220 --> 00:29.270 So whether it's a wax candle a glass of milk or even the human skin light doesn't just hit the surface 00:29.270 --> 00:35.570 and bounce off it as she goes into the surface and that scatters within the surface before leaving the 00:35.570 --> 00:36.540 skin again. 00:36.860 --> 00:43.250 So the light enters them arterial and then it is scattered in the material by a certain amount depending 00:43.250 --> 00:45.750 on certain parameters. 00:45.830 --> 00:50.360 Some light leaves the surface at different points in which it entered. 00:50.360 --> 00:56.390 Now the more the distance that the light travels before exiting the more it will be absorbed so you 00:56.390 --> 01:00.990 will have less of an effect when it's thick vs. when it's thin. 01:01.250 --> 01:05.160 So thicker areas will absorb more than thinner ones. 01:05.180 --> 01:11.330 Now most shade as we have used so far are an example of direct surface scattering. 01:11.330 --> 01:18.830 So a diffuse shader is how the surface reacts to light a gloss shade or again is how the surface reacts 01:18.830 --> 01:27.170 to light subsurface scattering is a form of indirect surface scattering where the light enters the material 01:27.350 --> 01:30.310 and to give you a real world example of this. 01:30.320 --> 01:33.380 And I'm sure you might have played with the lights before. 01:33.410 --> 01:40.750 I'll just show you a small clip now of what happens when a simple hand goes over the top of a lightsource. 01:41.750 --> 01:44.480 So here we have a simple light. 01:44.480 --> 01:48.090 I'm using my phone lights here and I've got a piece of cardboard. 01:48.140 --> 01:54.500 As we approach the actual light itself this is an example of subsurface scattering. 01:54.500 --> 01:58.920 The light is entering that cardboard and actually being bounced about. 01:59.060 --> 02:05.150 And if we go and grab my hand as we start to move toward you can now see with the fingertip itself is 02:05.150 --> 02:07.800 starting to scatter red light. 02:08.030 --> 02:14.090 And if I move my finger down across the light you can see that the light is coming through the finger. 02:14.090 --> 02:20.150 In fact down this gap in between the fingers it is in fact subsurface scattering again the light is 02:20.150 --> 02:25.200 not getting through directly rather than indirectly through the finger. 02:26.550 --> 02:32.620 So before we go ahead and start playing about with the subsurface scattering though. 02:32.800 --> 02:35.390 I'll just want to show you these two scenes. 02:35.400 --> 02:41.000 The only difference between these two scenes is the lighting itself. 02:41.040 --> 02:46.520 They're just spheres with a subsurface scatting material applied to them. 02:46.680 --> 02:49.770 The first one has a three point lighting set up. 02:49.830 --> 02:53.430 The second one you can see is very much extreme. 02:53.430 --> 02:56.490 The light is to the slightly to the right and behind. 02:56.620 --> 03:03.450 And it is just a single Sprite spotlight and that produces a dramatically different effect. 03:03.510 --> 03:11.160 So is important here when we compare the two images that you realize that lighting can make a big impact 03:11.190 --> 03:12.420 to your scene. 03:12.450 --> 03:18.570 So it's quite useful to get that right first before you start tweaking your materials because you could 03:18.570 --> 03:26.910 be tweaking your materials based upon the lighting rather than basing it upon what the actual material 03:26.910 --> 03:29.330 should be resembling. 03:29.340 --> 03:35.520 So now we've explored these particular topics let's go play with the subsurface scattering node a rim 03:35.520 --> 03:36.750 blender. 03:36.870 --> 03:40.910 So I have gone ahead and opened up a brand new blender file. 03:40.920 --> 03:47.370 Now there's one important thing that you should know before we get going is that subsurface scattering 03:47.670 --> 03:55.610 is only supported on GP use from the latest version of Blender which is currently two point seven seven. 03:55.620 --> 04:02.040 Before that if each trying new subsurface scattering on your GP you you'll end up with it not rendering 04:02.040 --> 04:03.500 you'll get an error. 04:03.520 --> 04:07.270 And what will happen is the Rendell come out and it'll just be blank. 04:07.370 --> 04:12.630 I just popped over to my P.S. In fact the balls that you've just seen I rendered on my p.c and I had 04:12.630 --> 04:18.720 two point seventy six installed on that particular computer and I had made it on my Mac when over the 04:18.720 --> 04:24.450 peasey for rendering and found that everything was black had confused me for a few moments until I realized 04:24.450 --> 04:30.270 that I was just running an older version where the GP who was not supported for subsurface scattering 04:30.870 --> 04:33.280 the cpq has always been so that's fine. 04:33.390 --> 04:38.460 So if you are finding your having rendering problems do make sure you've got the latest version of Blender. 04:38.670 --> 04:45.500 So without any further adieu let's go and delete this cube and add in the monkey. 04:45.510 --> 04:46.740 Hello Suzanne. 04:46.740 --> 04:54.870 We're going to then get a subsurface division modifier just to make her a little smoother and add in 04:54.870 --> 04:56.270 a smooth shading. 04:56.590 --> 04:58.570 Okay I'm happy with that. 04:58.680 --> 05:02.160 Let's go ahead now and play with the materials. 05:02.160 --> 05:04.850 Has a couple of ways that we can obviously get to the materials week. 05:04.890 --> 05:10.910 We're going to need the node editor in a moment so let's go ahead and open up the node editor. 05:11.310 --> 05:11.960 There we go. 05:12.150 --> 05:17.010 And we can create new material on the node editor or in the materials properties over here it doesn't 05:17.010 --> 05:17.740 matter. 05:17.820 --> 05:23.340 And once we've created that let's zoom in so you guys can see what's going on and we can see at the 05:23.340 --> 05:24.940 moment it's got a diffuse shader. 05:24.960 --> 05:32.070 Now eventually when we build up the actual layers that exist for the skin we're going to use a monkey 05:32.070 --> 05:33.270 as an example here. 05:33.350 --> 05:34.990 A We will end up with a diffuse shade. 05:35.010 --> 05:37.610 But for the moment we can just get rid of it. 05:37.650 --> 05:40.650 If I had one to get rid of everything just the diffuse shade. 05:41.490 --> 05:45.870 So just start with that one subsurface scattering shader. 05:45.870 --> 05:49.390 So under shaders we got subsurface scattering. 05:49.440 --> 05:56.880 Now sometimes abbreviated to just three S's as well so if you ever see s s s that means sub surface 05:56.970 --> 05:57.940 scattering. 05:58.110 --> 06:03.230 And let's turn my view port to rendered mode. 06:03.270 --> 06:09.930 Now we can already see this compared to diffuse is already getting light coming through certain directions. 06:09.990 --> 06:15.160 Now not quite sure where my lamp is in the scene so let's just set up the lighting first. 06:15.240 --> 06:23.610 If I'm going to put the lights almost directly behind Suzanne so we can really see the light basically 06:23.610 --> 06:26.160 come through the ears to get to the front view. 06:26.160 --> 06:28.590 Pull that down can't really see much here. 06:28.590 --> 06:29.380 There we go. 06:30.220 --> 06:36.010 And I'm going to make that quite bright was going make it five thousand or something so let's just check 06:36.010 --> 06:40.300 and see what that looks like Okay five thousand is going to be too much. 06:40.300 --> 06:42.500 Again that's was around to the front. 06:44.820 --> 06:46.540 Zoom in and see what's going on. 06:46.590 --> 06:52.590 So we're losing all the detail in the years at five thousand So that is far too bright so we can play 06:52.590 --> 06:57.900 this to our hearts content 2000 to hyatt's get down to five hundred k. 06:57.930 --> 06:59.710 That's possibly there. 06:59.730 --> 07:07.050 Let's drop it to 300 and we can see that light is coming through the chin as well Suzanne here as well 07:07.050 --> 07:07.740 as the years. 07:07.810 --> 07:09.380 I am happy with that so. 07:09.490 --> 07:13.290 And then right click back on Suzanne so I can see the subsurface scattering. 07:13.470 --> 07:17.370 And there are a series of options there's only one outputs. 07:17.520 --> 07:21.200 But when it comes to subsurface scattering there's a lot of options. 07:21.330 --> 07:24.300 So the first option at the top is the fall off. 07:24.360 --> 07:29.010 Now this is how quickly the light falls off as it goes through. 07:29.010 --> 07:36.540 And these are just different distributions cubic I believe falls off quick of an Gaussian and I would 07:36.540 --> 07:42.930 have to look up that one on Wikipedia but approximate as we can see here it's an approximation to physically 07:42.930 --> 07:47.660 based volumes scattering which is why it's the default setting the colour. 07:47.680 --> 07:49.340 Well that's like you base colour. 07:49.650 --> 07:54.020 And that you can get a texture being plugged into here as well if you want to. 07:54.180 --> 08:00.290 So we say that to whatever colour that is like your base colour for the model itself. 08:00.330 --> 08:05.820 So if I go ahead and make that slightly peachy we can see that colour of we go make vasseur a deeper 08:05.830 --> 08:06.980 read it. 08:07.100 --> 08:10.890 Well it turns red the scale we're going to come back to the scale. 08:10.920 --> 08:17.180 It's basically a multiplier for these next three options under radius if we cast our eyes over certain 08:17.190 --> 08:20.550 material properties you'll see it's not collapsed here at all. 08:20.550 --> 08:23.480 It's literally just three options that you can get to. 08:23.760 --> 08:30.300 So the radius will come back to in a few moments because the texture blur would only change things if 08:30.300 --> 08:32.280 you've got a texture plugged in here. 08:32.280 --> 08:35.440 And normal is for normal maps coming in as well. 08:35.550 --> 08:41.070 The reason why this has a purple set there's because it has the three values here. 08:41.160 --> 08:45.750 Now with a radius you'd usually think it was like X Y and Z. 08:49.690 --> 08:51.280 In this case it isn't. 08:51.280 --> 08:57.200 These are r.g. devalues something to set the colour back to white for the moment. 08:57.370 --> 09:01.970 So you get a good representation going to make it pure white so value of one throughout. 09:03.070 --> 09:07.180 So what we should find here is and I'm going adjust them over here so I don't have to keep having that 09:07.180 --> 09:16.900 dropped down if I turn the blue channel and the green channel down to zero we should see that it only 09:16.900 --> 09:20.140 scatters red only red light actually exits. 09:20.140 --> 09:24.510 The model itself even though the light coming in is white. 09:24.760 --> 09:30.040 And again if we go ahead make that zero the nothink will come through before we go in at this one because 09:30.040 --> 09:31.200 it's R G B. 09:31.240 --> 09:33.780 This should have green light coming through. 09:34.060 --> 09:37.020 Now we can take a while to actually set these up. 09:37.030 --> 09:43.810 And truth be told you're not just going to be using one node in order to get a realistic material. 09:43.810 --> 09:51.910 Those balls we saw earlier were just a one node but our skin is more complex than just one node can 09:51.910 --> 09:52.350 do. 09:52.480 --> 09:57.440 Now you can certainly make this into a group and perhaps use it again and again if you wanted to. 09:57.550 --> 10:03.800 But in general you've got to think of your skin as a series of layers. 10:03.820 --> 10:12.940 Now with this subsurface scattering the way that I would tend to set this up and it varies from project 10:12.940 --> 10:17.450 to project would be to duplicate the subsurface scattering. 10:18.310 --> 10:19.290 Twice. 10:20.160 --> 10:23.530 So then we've got three layers. 10:23.970 --> 10:25.800 So I'm going to call this light deep. 10:26.770 --> 10:30.520 This horn sort of medium and this one's near the surface. 10:30.700 --> 10:35.780 Now with all shade as we're going to have the user mix shader to put them all together. 10:36.700 --> 10:42.670 And if you think about the this it's the deepest will be dark ready colour whether the blood is there. 10:42.670 --> 10:46.000 We've got so like the fatty layer so we'll make that slightly lighter. 10:46.120 --> 10:52.300 And then we've got the surface of the skin and it well it will depend on the ethnicity of the character 10:52.300 --> 10:57.310 you're doing but in this case I'm going to stick with myself so I'm going to make that quite light because 10:57.310 --> 11:02.080 the surfaces of the skin in places can actually be quite light. 11:02.290 --> 11:09.910 I need to build these up now using some Mc shaders and we also want to add in a diffuse shader along 11:09.910 --> 11:17.410 with this being mixed and a gloss shade because the surface of the skin does have a bit of spec clarity 11:17.410 --> 11:18.420 to it. 11:18.550 --> 11:21.500 And of course that means it's time for a challenge. 11:24.500 --> 11:25.170 Okay. 11:25.190 --> 11:33.470 I'd like you to create your nodes set up so you're going to be linking three subsurface shaders representing 11:33.470 --> 11:36.160 three layers beneath the skin. 11:36.530 --> 11:41.830 Then link the final two surface layers a diffuse angle of shader. 11:41.930 --> 11:49.580 So there we've got our indirect and direct scattering use the sand for practice or your own head. 11:49.580 --> 11:51.410 It doesn't matter at this stage. 11:51.470 --> 11:55.700 I'm going to be using susanne's if you want to follow along with Suzanne the monkey. 11:55.700 --> 11:57.430 That's absolutely fine. 11:57.770 --> 12:01.100 And play with your settings until you're happy. 12:01.220 --> 12:07.040 Now don't worry about the cloche shader because that might make the model look a bit waxy as if it was 12:07.040 --> 12:10.380 a are made out of a wax essentially. 12:10.430 --> 12:15.900 But we'll be dealing with that shortly in Cape balls video and give that a go. 12:18.350 --> 12:19.030 Okay guys. 12:19.040 --> 12:20.010 Welcome back. 12:20.150 --> 12:21.740 Let's go play with these notes. 12:21.830 --> 12:22.950 Over in blender. 12:23.880 --> 12:31.230 Okay so just before we start this I know that if we hop into rended mode we've only got one light from 12:31.230 --> 12:36.090 the back and that's not going to be good to work out whether he's got the colour right. 12:36.090 --> 12:46.080 So I am going to make this window a wee bit bigger for a moment and let's grab a top view and set some 12:46.080 --> 12:48.720 duplicate lights just around here. 12:48.720 --> 12:53.880 I'm not going to worry about setting them up any further than that just to create a a three point lighting 12:53.880 --> 12:59.670 that's go so they can review and move that round render it out at the end to see what it looks like. 13:01.040 --> 13:02.500 Kate almost there. 13:02.830 --> 13:04.340 He fills the frame. 13:04.500 --> 13:07.200 Oh that's cold back ever so slightly there we go. 13:07.480 --> 13:08.700 Definitely fills the frame now. 13:08.890 --> 13:10.690 Let's hop into rended mode and see what it looks like. 13:10.690 --> 13:13.260 Okay there's much more light in there now. 13:13.450 --> 13:15.330 I'm happy with that. 13:15.340 --> 13:21.670 So let's go ahead and start playing with the notes sarve selected the monkey's head again because I 13:21.670 --> 13:23.470 was still on a lamp. 13:23.710 --> 13:28.420 So so currently we've only got this subsurface scattering no plug in. 13:28.500 --> 13:37.660 So let's go ahead and add in a mix shade up pop that's in place there. 13:38.080 --> 13:41.120 And I'm going to join it here. 13:41.540 --> 13:44.020 So then we've got these two shaders next to one another. 13:44.020 --> 13:48.550 Now what we have got here if I look at the radius is it's still a bit funny here. 13:48.550 --> 13:54.850 And what you'll find is you'll end up with a very very noisy image with subsurface scattering. 13:54.940 --> 13:58.120 If your settings here in the radius. 13:58.150 --> 14:05.730 How far light is being scattered is completely different to what happens with the actual base colour. 14:05.720 --> 14:11.650 So you got a base colour of near enough red here almost pure red looking at it's not quite. 14:11.740 --> 14:13.080 But it's almost pure red. 14:13.120 --> 14:16.020 Now we're only scattering. 14:17.290 --> 14:17.670 Red. 14:17.670 --> 14:17.980 Green. 14:17.980 --> 14:19.400 Green light. 14:19.450 --> 14:21.650 So that's not going to work very well. 14:21.660 --> 14:23.230 It's going to end up very noisy. 14:23.260 --> 14:25.660 You're basically confusing the system at that point. 14:25.810 --> 14:31.670 So if we start scattering some more red and less green because there's no green to scatter. 14:31.930 --> 14:38.550 We end up with a clean image and the same will have to be applied down here so the radius here are going 14:38.560 --> 14:40.920 to lower these as we go. 14:40.920 --> 14:43.560 This go for points to point to. 14:43.750 --> 14:50.140 I think the other warms a little bit on the high side actually or lower side of number four point three 14:50.140 --> 14:51.140 here. 14:51.180 --> 14:54.580 Again these are all things that we can tweak over and over and over again. 14:54.610 --> 14:55.810 We're going to need another mic shade. 14:55.810 --> 15:00.340 I'm just going to simply duplicate it and plug in this. 15:00.400 --> 15:03.240 Now this is going to be the top most layer. 15:03.460 --> 15:05.870 And we don't want it scattering that much at all. 15:05.890 --> 15:11.850 So I'm go on the very top but there one just spinning if I'm going to make these values very low so 15:11.860 --> 15:17.680 still scattering but not very much because that's that represents the layer just under the skin. 15:17.710 --> 15:23.920 Look at that that's coming together now really well and then zoom in on the head area specially those 15:23.950 --> 15:27.090 is because they're the thinnest part on this particular model. 15:27.100 --> 15:28.770 So we can see that coming through. 15:28.780 --> 15:30.990 Now what you're not really getting at the moment. 15:30.990 --> 15:34.990 It's it's there but not fully is the detail itself. 15:34.990 --> 15:40.060 In fact the detail is mainly being shown up because of the three point lighting system rather than anything 15:40.060 --> 15:40.730 else. 15:40.750 --> 15:44.720 However we can help that by adding the first surface layer. 15:44.860 --> 15:50.050 So it's go ahead and hand in a diffuse. 15:51.700 --> 15:57.790 And we're going to need another MC shader and we'll worry about other things like the values of all 15:57.790 --> 16:01.410 of this and we've got a colour white here that's going to be too bright. 16:01.410 --> 16:07.630 I'm going to actually lower it down to roughly what I have on for my skin that's just a rough guess 16:07.630 --> 16:08.160 there. 16:08.230 --> 16:14.030 Of course depending on the air from this sea of whatever you're making you can pick any colour you want. 16:14.050 --> 16:19.190 Hey you can have an alien one if you wanted and colour Him mean green. 16:19.480 --> 16:22.430 Okay so I'm going to go back to that rough colour I've got here. 16:22.450 --> 16:24.850 So now we start to see some more detail. 16:25.000 --> 16:26.790 I whacked this all the way up here. 16:26.800 --> 16:32.440 Then we've got off the full diffuse few shader and we can lower that back down and just have just the 16:32.440 --> 16:33.550 sub scattering. 16:33.550 --> 16:38.060 Of course we want a mix of everything as we go through this first layer here. 16:38.080 --> 16:41.810 We definitely want more of the base layer coming through. 16:41.860 --> 16:43.540 I think we do I'm going to play with it a bit. 16:43.540 --> 16:43.940 There we go. 16:43.930 --> 16:47.110 He is have gone just that little bit red up there. 16:47.110 --> 16:51.440 The thinnest part not so much of this coming through. 16:51.460 --> 16:57.100 We do want some of the diffuse and then take that to maybe around 40 percent or so and then we need 16:57.100 --> 17:04.210 the final layer so we can then need yet another mix shader So I'm going to duplicate that and add in 17:04.270 --> 17:05.470 a gloss. 17:05.500 --> 17:06.260 Shake it up. 17:07.870 --> 17:11.940 Now this will obviously add highlights to our model. 17:12.130 --> 17:17.320 And if we go all the way we end up with a very shiny surface and we go all the way back. 17:17.410 --> 17:21.030 It ends up fully well fully whatever this area is here. 17:21.020 --> 17:25.760 So it's a mixture of the diffuse and the subsurface scattering notes. 17:25.810 --> 17:31.540 So I'm going to bring that up to around 15 to 20 percent just so we start getting highlights. 17:31.540 --> 17:36.130 Now this is what I mean by it starts to look a bit plasticky or a bit waxy. 17:36.140 --> 17:41.080 We can certainly increase the roughness if the roughness is too low it's just going to look well very 17:41.080 --> 17:42.940 very shiny if it's too high. 17:42.940 --> 17:48.640 We're going to lose some of that detail in the highlights some more said it's about point three. 17:48.640 --> 17:53.600 So we've got some subtle highlights there but we're going to deal with the positioning of those highlights 17:53.630 --> 17:57.330 as there's plenty of ways of doing it but not in this particular setup. 17:57.580 --> 18:03.140 So let's just hit the render key and see what this looks like when it's rendered out. 18:03.190 --> 18:06.080 I've not got a set particularly high on samples. 18:06.300 --> 18:10.450 I don't know what I've got it set to is set to 50 samples at the moment. 18:10.450 --> 18:12.100 I'm quite happy with that. 18:12.100 --> 18:16.260 It's a bit pink so I could go back or not here. 18:16.270 --> 18:18.160 I want to get back to the node. 18:18.160 --> 18:22.740 Ed it's probably this diffused colour here that's bringing that out so if I make that a bit lighter 18:23.020 --> 18:28.680 and of course I'm going to really ramp the samples up now 300 too high. 18:28.680 --> 18:30.240 That's just silly at this stage. 18:30.400 --> 18:38.830 When I go to 200 just to get a temporary feel of how this is looking I wouldn't ever recommend rendering 18:38.830 --> 18:45.320 it high samples just for a test renders I mean 200 is not particularly high but it's not low either. 18:45.340 --> 18:46.850 You can see this as well. 18:46.870 --> 18:51.820 It was at 50 it's now 200 it's going to take four times longer than it did before and we can check that 18:51.810 --> 18:58.990 because our last render was just over eight seconds so I reckon this was going to be around 35 40 around 18:58.990 --> 18:59.630 there anyway. 18:59.770 --> 19:02.060 So it's just finishing off here. 19:02.080 --> 19:04.540 There you go 30 52 Not bad. 19:04.540 --> 19:06.010 We're eight times four is 32. 19:06.010 --> 19:06.670 So there we go. 19:06.850 --> 19:08.460 So that is looking pretty good. 19:08.470 --> 19:10.150 I'm impressed with that. 19:10.150 --> 19:16.510 How are you guys getting on did you do this with Suzanne or did you decide to make it start going on 19:16.510 --> 19:18.950 straightaway with your head that you've been working on. 19:19.030 --> 19:20.830 A suggestive you haven't done that. 19:20.830 --> 19:26.680 You go and apply the knowledge you've just learned immediately by applying this sort of set up and play 19:26.680 --> 19:32.630 with it to your particular head model that you're working on as a way share in the discussions. 19:32.680 --> 19:35.380 And I will see you in the next lecture.