WEBVTT 00:00.450 --> 00:08.700 Welcome to light portals in this video you will learn how to use light portals understand the limitations 00:08.730 --> 00:13.720 of their use see that they can dramatically increase quality. 00:13.860 --> 00:21.240 Given a fixed number of samples and see they're especially useful for indoor environments little by 00:21.240 --> 00:23.220 environmental lighting. 00:23.520 --> 00:29.590 So to talk about portals we need to talk first about cycles and how the lighting works. 00:29.850 --> 00:32.960 Light rays are fired out from the camera. 00:32.970 --> 00:36.640 The active camera until they hit a light source. 00:36.780 --> 00:42.240 Now this sounds a bit counterintuitive in to you imagine well that light source could be projecting 00:42.240 --> 00:46.630 light in any direction and to make sure we don't waste time. 00:46.740 --> 00:55.020 The Rays are fired from the camera so that we are capturing the light that only the camera can see. 00:55.760 --> 01:02.720 With the lamp blender knows where the light sources so only fires rays that will eventually hit the 01:02.720 --> 01:03.550 light source. 01:03.620 --> 01:07.570 And this often ends up with a nice clean image. 01:07.970 --> 01:15.350 Now with a missive materials blender doesn't know where the light sources so when the camera fires those 01:15.350 --> 01:18.560 rays some of them never reach a light source. 01:18.650 --> 01:21.460 And this introduces more noise. 01:22.610 --> 01:30.020 With environmental lighting when you've got a sky map in the scene or an HDR high dynamic range environmental 01:30.020 --> 01:38.120 or lighting in an interior with only windows letting light in the Rays bounce around a lot and only 01:38.120 --> 01:42.420 a few actually manage to go out the window and reach the light source. 01:43.400 --> 01:47.710 This introduces a lot of noise in the final image. 01:47.720 --> 01:50.150 Given a certain number of samples. 01:50.950 --> 01:53.040 So how do portal's help. 01:53.260 --> 01:57.800 Well portal's helped by telling Glendale where to aim those rays. 01:57.820 --> 02:01.690 This produces much less noise in the final image. 02:01.960 --> 02:04.870 However they do have some limitations. 02:05.050 --> 02:12.460 Poor tools are a cycle's lighting feature which means that they won't work externally to blend and they 02:12.460 --> 02:17.230 won't work with the blender internal rendering engine. 02:17.710 --> 02:20.650 They increase light calculation time. 02:20.650 --> 02:27.520 However that's offset by the fact you don't have to render as quickly so they produce much less noisy 02:27.520 --> 02:28.770 environments. 02:29.410 --> 02:37.560 Poor tools only work with environmental lights using them otherwise can reduce quality. 02:39.060 --> 02:40.850 And they have little impact. 02:40.860 --> 02:46.270 If you put something in the way so that's going to have a look at couple of examples before we hop into 02:46.270 --> 02:47.040 a blender. 02:47.220 --> 02:54.840 So this is in a missive plane that's placed outside that hole in the in this box and there is no portal. 02:55.050 --> 02:59.790 If we put a portal in the way when it actually looks worse and noisier. 02:59.940 --> 03:02.680 So that's an example of it not working. 03:02.850 --> 03:08.490 And in fact making things worse with a missive plane that's outside. 03:08.550 --> 03:11.290 So what happens if we bring the missing plane. 03:11.310 --> 03:13.400 So it's faking being the window. 03:13.410 --> 03:17.060 Well this is with no port that's a relatively clean image. 03:17.250 --> 03:21.960 In the missive plane acting as the window and a portal there to guide it. 03:21.980 --> 03:24.940 Well you see it actually makes it worse again. 03:25.020 --> 03:27.470 Now let's have a look at an environmental light. 03:27.480 --> 03:31.160 So at this point the environment is just white. 03:31.170 --> 03:38.250 To be consistent and there is no portal you can see that that image is very hard to even work out what 03:38.250 --> 03:38.820 that is. 03:38.820 --> 03:42.100 Is it a cube or is it just a bunch of noise. 03:42.120 --> 03:47.250 Well with a poor tool it makes a phenomenal amount of difference. 03:47.400 --> 03:49.310 And just for example. 03:49.320 --> 03:57.680 This is a sunlamp placed outside with a thousand samples and you can see yes the lighting slightly differently 03:57.690 --> 04:00.000 because it's not an environmental light. 04:00.000 --> 04:07.520 It's a point light source in the sky being a sunlamp it's still noisier than the previous one. 04:07.560 --> 04:13.210 So some examples of when you stick something in the way are we're going to see some familiar faces here. 04:13.620 --> 04:17.820 A There's some bunnies lamps and bowling pins and a chess set. 04:17.820 --> 04:23.220 So we have four different scenes here that we're going to run through and show you the difference. 04:23.220 --> 04:29.120 The top two are with and without a portal and so are the bottom two. 04:29.450 --> 04:35.760 However the bottom two have a glass window in the way so let's go have a look at these in a bit more 04:35.760 --> 04:36.570 detail. 04:36.660 --> 04:40.940 So this is the scene rendered with a portal. 04:41.660 --> 04:47.150 So you can see it's only 30 samples in this case so there is still noise in the scene. 04:47.150 --> 04:54.200 It took about 30 odd minutes to do this particular scene render on a g.t. X 980 just to give you an 04:54.200 --> 05:01.160 idea of times taken even that 30 samples because there's there's a lot of complexity in this particular 05:01.160 --> 05:01.980 scene. 05:02.360 --> 05:08.900 Now if we see it without support or you can see that it's much more noisy especially in the darker areas 05:08.930 --> 05:10.610 of the scene. 05:10.610 --> 05:15.950 Now it changes slightly when you go and put a window in. 05:15.950 --> 05:18.730 So at the moment that's just a hole in the wall. 05:18.830 --> 05:20.180 Go and put a window in. 05:20.360 --> 05:25.970 Well much less light actually enters the room because it's bouncing in and out of that glass. 05:26.030 --> 05:27.920 So less light comes in. 05:27.920 --> 05:32.610 So one of these has a portal and this next one does not. 05:33.550 --> 05:35.380 What did you see the difference there. 05:35.390 --> 05:36.520 This is before. 05:37.310 --> 05:38.580 And this is after. 05:39.680 --> 05:41.660 Well I struggle to see the difference there. 05:41.710 --> 05:47.290 And that just goes to show that if you stick something in the way like glass that you think well actually 05:47.290 --> 05:52.330 if it's an environmental light in the air yet of the glass it will help guide the Rays. 05:52.330 --> 05:57.310 No one fortunately certainly at the moment that doesn't help at all. 05:57.310 --> 06:01.500 In fact in this case it seems to make no difference whatsoever. 06:01.960 --> 06:07.290 So let's now hop on over into blender and play with some light portal's. 06:08.400 --> 06:15.300 So let's start off with a basic cube in our scene so I've opened up a brand new blender file and will 06:15.300 --> 06:17.080 take it from there. 06:17.100 --> 06:22.740 The first thing this I'm going to do is remove the lamp from this basic scene because it's no longer 06:22.740 --> 06:24.100 required. 06:24.420 --> 06:26.880 And we're going to add a different light source. 06:26.910 --> 06:30.590 So we're going to go to the world propertys. 06:30.640 --> 06:36.930 We're going to change the colour of the world to a white and just go ahead hit render and see how that 06:36.930 --> 06:37.750 comes out. 06:37.800 --> 06:40.680 That's exactly what I'll be expecting for it to happen. 06:40.680 --> 06:47.220 This cube is uniformly lit from the outside so we can't see any details because it's white all around. 06:47.220 --> 06:48.110 Perfect. 06:48.120 --> 06:54.150 So let's hop back into the 3-d view and let's make this cube much much much bigger. 06:54.150 --> 06:57.700 So hop into edit mode and scale it up. 06:59.210 --> 07:01.320 By let's make it 10 times bigger. 07:01.490 --> 07:03.410 And then we can exist in it. 07:03.590 --> 07:09.980 And I'm going to lift it up by 10 on the z axis 2 and that should place on the ground. 07:09.980 --> 07:14.550 Excellent so we can easily be inside here and have a switch to the camera mode. 07:14.590 --> 07:19.200 I'm inside it so you've created a fake building very quickly. 07:19.340 --> 07:22.130 The next thing I'm going to do is subdivide. 07:22.130 --> 07:24.440 This keeps on going to come out of a camera mode. 07:24.470 --> 07:30.020 I'm going to subdivide this cube a couple of times so I'm gonna use the tool shelf here. 07:30.090 --> 07:33.820 I want it so I can just remove some of these faces. 07:33.980 --> 07:41.070 So I'm going to go ahead here and remove a zigzag pattern going down. 07:42.310 --> 07:44.110 And for those too there why not. 07:44.110 --> 07:45.670 In fact let's just remove those. 07:45.670 --> 07:47.170 They're perfect. 07:47.170 --> 07:48.940 So let's delete. 07:48.940 --> 07:50.860 I want the faces gone sir. 07:50.860 --> 07:52.020 There we go. 07:52.030 --> 07:52.390 There we go. 07:52.390 --> 07:54.840 There is our funky window in the wall. 07:54.970 --> 08:01.090 And the final thing we're going to do before we actually start playing inside is to add a modifier which 08:01.090 --> 08:07.640 is a solidify which will make the walls for us and that's under generate solidify. 08:07.800 --> 08:11.650 And I'm going to increase the thickness to point one. 08:11.650 --> 08:15.670 Now one of the things you have to watch out here for is if you look through that there's a bit of a 08:15.670 --> 08:17.050 curve going on. 08:17.140 --> 08:24.460 And if we have a look in fact this is a very thick cube some was going to make it maybe point four so 08:24.460 --> 08:28.900 we can see more what's happening now as it's moving around the edge. 08:28.930 --> 08:30.790 Can we see an wireframe mode. 08:30.790 --> 08:33.370 More detail. 08:33.370 --> 08:35.350 It's not exaggerating it that much. 08:35.350 --> 08:41.740 But basically if you take even thickness It'll make sure that the thickness is applied evenly throughout 08:41.740 --> 08:42.480 the model. 08:42.730 --> 08:47.730 So let's hop inside and I'm going to move my camera about so I can see more. 08:47.770 --> 08:50.190 I'm going to use the walkaround feature. 08:50.190 --> 08:53.620 So we've got our window there. 08:53.620 --> 08:55.270 This is quite a large room. 08:55.300 --> 09:01.150 And I think I've just gone through so I'm just going to come out of wireframe and do that again. 09:01.630 --> 09:07.210 So I know when I pass there and I might want a wide angle lens in fact I think I do in this case. 09:07.380 --> 09:15.130 So I'm going to go ahead and change the camera properties so it has a wider focal length. 09:15.130 --> 09:16.280 I'm going to go for 80. 09:16.340 --> 09:17.740 There we go see much more. 09:17.740 --> 09:20.850 So let's see how this looks at the moment. 09:21.430 --> 09:22.060 There we go. 09:22.060 --> 09:26.740 We have quite a noisy scene now on the render results. 09:26.740 --> 09:27.660 Down at the bottom. 09:27.670 --> 09:34.870 I'm going to change your it's slot one to slot two so we can compare in a few moments and I'm just going 09:34.870 --> 09:38.720 to make this a bit larger so we can compare them much more closely. 09:38.740 --> 09:40.740 So let's now hop to the 3-d view. 09:40.790 --> 09:51.580 Now in order to add a now in order to go ahead and add in a portable is actually a type of lamp some 09:51.580 --> 09:56.290 going to add the portal here and I'm going to cover all four windows with it if they're close together 09:56.290 --> 09:58.210 you can cover them all together. 09:58.210 --> 10:03.310 Obviously the number of portals if you have too many of them may add up and cost you more in calculation 10:03.310 --> 10:03.790 time. 10:03.820 --> 10:08.950 But in this case we can just cover this middle square because it doesn't really matter compared to the 10:08.950 --> 10:10.310 other ones around it. 10:10.360 --> 10:12.670 We could of course add four portals. 10:12.670 --> 10:23.620 So let's go in add a lamp of type area and in the properties for the lamp we can change it so says portal. 10:23.620 --> 10:26.350 That's all we need to do in terms of setting that up. 10:26.560 --> 10:33.880 Apart from we need to rotate it round so I'm going to rotate it's on the y axes and ungless looking 10:33.880 --> 10:36.030 down there so it's going to be why by 90. 10:36.070 --> 10:40.350 You see that dotted line that white dotted line now orange coming out of it. 10:40.360 --> 10:42.070 That's the direction it wants to face. 10:42.070 --> 10:44.710 The light is going that way. 10:44.890 --> 10:46.630 So the final thing here is to do the size. 10:46.630 --> 10:51.370 Now there's an option over in the properties to have it square or rectangular. 10:51.370 --> 10:56.610 So you can have it different proportions under the leave it set square since it's there. 10:56.690 --> 10:59.980 And I'm going to just go up and up and up. 11:00.040 --> 11:04.030 I think this is end up going to be 10 No 12. 11:04.090 --> 11:04.470 There we go. 11:04.470 --> 11:07.980 So 12 covers the entire thing I'm going to add a little extra. 11:08.050 --> 11:15.160 And now when we go back inside the building and hit render we should end up with a much less noisy image. 11:15.160 --> 11:19.030 Now I've got the default settings here so that's 10 samples. 11:19.030 --> 11:22.580 And the difference between that and. 11:22.600 --> 11:30.020 Okay that was a great example I didn't switch to slot before hitting render cilice just render it without. 11:31.800 --> 11:32.480 So there we go. 11:32.490 --> 11:37.980 This one is much noise zarine slot to them with out. 11:38.370 --> 11:45.720 Now one thing that should be noted at this point is that the rough render did take just over three seconds 11:45.720 --> 11:49.530 and the other one was I think it was five and a bit seconds. 11:49.530 --> 11:52.350 Well we can quickly go and check it would go to slot 1. 11:52.350 --> 11:57.780 I'm going to turn my area lamp back on and then render again. 11:57.780 --> 12:03.120 Now this isn't these aren't optimal squares for this particular render they need to be made a bit smaller. 12:03.120 --> 12:03.620 So there you go. 12:03.620 --> 12:05.830 Five point six so it's taking a bit longer. 12:05.940 --> 12:12.740 But let's see if doubling the sample counts on slot three makes a difference because. 12:13.690 --> 12:14.580 I don't think it. 12:14.590 --> 12:22.420 Well I think that's the one at stenn samples with a portal is going to be much cleaner than 20 samples 12:22.440 --> 12:24.070 with out a portal. 12:25.660 --> 12:32.660 So it should take at least twice as long to do this is the one with the portal that 20 samples. 12:32.800 --> 12:38.290 And let's go to slot four and do the one with out the portal just to demonstrate that it's still going 12:38.290 --> 12:39.680 to be noisy. 12:40.590 --> 12:44.080 And we can see straightaway it's going to be much more noisy. 12:44.250 --> 12:50.040 So let's just have a look through these then so we've got slot 1 which was 10 samples with a portal 12:50.220 --> 13:00.030 slot who is 10 samples without a portal slot three is 20 samples with a portal and slot four is 20 samples 13:00.030 --> 13:01.230 without a portal. 13:01.230 --> 13:07.290 So we compare the one that's taken nearly the same time as the first one with a portal. 13:07.350 --> 13:10.840 You can see it's still much much cleaner. 13:10.920 --> 13:15.440 So now we understand about portals and how to put them into a scene. 13:15.600 --> 13:17.600 I've got a small challenge for you. 13:18.320 --> 13:22.290 I would like you to add some portals to your interior. 13:22.430 --> 13:29.450 So add in environment texture or indeed just adjust the world surface like I did in the example hide 13:29.480 --> 13:32.340 or remove any other light sources. 13:32.360 --> 13:34.170 So it's a fair comparison. 13:34.640 --> 13:37.830 Render your interior at about 20 sample. 13:39.330 --> 13:48.570 Render your teria about 20 samples first for a baseline ad like poor tools to those windows and then 13:48.570 --> 13:53.450 render the scene and share in the discussions the difference it's made. 13:53.460 --> 13:55.730 Pause video now and give that a go. 13:57.330 --> 13:58.350 Okay guys welcome back. 13:58.350 --> 14:01.500 Let's go add some portal's to our interior. 14:01.500 --> 14:04.450 So I've made sure my camera is in roughly the right position. 14:04.470 --> 14:11.150 I managed to make it a little bit wonky and the first thing that I'm going to do is do the render. 14:11.160 --> 14:13.290 But make sure the render settings are fair. 14:13.290 --> 14:15.960 So let's just check the number of samples. 14:15.960 --> 14:17.850 The number of samples is 50. 14:17.850 --> 14:20.280 Let's drop it down to 20. 14:20.280 --> 14:24.340 Go ahead and hit render the moment that's done. 14:24.370 --> 14:29.400 Oh I haven't added my environmental lighting yet or remove the other lights from the scene. 14:29.400 --> 14:31.410 I'll be back in a few moments. 14:31.410 --> 14:32.220 There we go. 14:32.220 --> 14:34.830 I've added an environmental light. 14:34.830 --> 14:40.680 It's just going to be a white one for the moment and now I've added that I just can see how that renders 14:40.770 --> 14:43.780 out looking pretty noisy at the moment. 14:43.780 --> 14:46.500 Be interesting to see whether it makes a difference. 14:46.590 --> 14:52.830 Once we add light portals and the reason why I say that is great cause there's a lot of gaps in the 14:52.830 --> 14:58.050 in the in the building at the moment which may cause or may not cause some problems. 14:58.170 --> 15:00.830 But there we go that's gives us a nice base level. 15:00.840 --> 15:04.220 Now I'm going to go ahead and add portals to the rest of these. 15:04.230 --> 15:05.770 Now I've got two choices. 15:05.910 --> 15:13.260 In this particular case I could go in and light portals to the original mesh and then re append them 15:13.290 --> 15:14.620 into the scene. 15:15.000 --> 15:21.940 Or I could stretch one along this entire wall for instance and then the rest groups too. 15:21.990 --> 15:28.800 In this case I am going to do that rather than modelling modifying the original having to reimport and 15:28.800 --> 15:30.780 change over these bits. 15:30.780 --> 15:32.360 Not going to do that at the moment. 15:34.780 --> 15:39.100 And there we go so I've added several portals into my scene. 15:39.100 --> 15:46.630 I think that's for future iterations I probably will make the poor tour with in the models themselves 15:46.930 --> 15:53.740 so that I never have to redo this but for the sake of this particular model I've gone ahead and done 15:53.740 --> 16:00.180 it anyway and I'm just going to go ahead and render the image so I've overwritten my original. 16:01.190 --> 16:02.400 Which is pretty silly. 16:02.640 --> 16:09.450 Okay so straightaway I can see that this particular render I inadvertently overwrote my first one for 16:09.450 --> 16:10.440 comparison. 16:10.440 --> 16:14.900 This one's taking as significantly less time. 16:14.910 --> 16:20.600 I can see straight away it's quick of the rendering with the light portal took one minute twenty four. 16:20.800 --> 16:27.120 And this was already on 24 seconds because it's counting up and it's an I don't know about the quality 16:27.120 --> 16:27.330 though. 16:27.360 --> 16:31.930 This is this is going to be one of these things where I am not sure whether the big holes in here are 16:31.930 --> 16:35.410 letting enough light in any way that we won't see much of a difference. 16:35.460 --> 16:36.470 But now it's rendered. 16:36.480 --> 16:38.200 Let's go and have a look. 16:38.220 --> 16:44.050 I'm going to make this as big as I possibly can for comparison so I look through the doorway here. 16:44.130 --> 16:47.530 And this is with portals without. 16:48.000 --> 16:56.100 With Okay I think in this particular instance portals aren't going to help us until I've got this roof 16:56.190 --> 16:57.830 sealed in. 16:58.020 --> 17:03.330 I can do a few checks to see whether that is the case but otherwise I think that's just not letting 17:03.510 --> 17:05.910 or is letting enough light in already. 17:05.930 --> 17:12.270 The camera is finding a light source and that's especially true at the moment because the camera is 17:12.270 --> 17:14.730 facing these big gaps. 17:14.730 --> 17:20.700 There is a lot of light that will naturally just bounce off of these floor bits etc and automatically 17:20.700 --> 17:23.620 end up hitting this sky box in the background. 17:23.650 --> 17:28.440 That's something to bear in mind the areas perhaps where that's not the case where it doesn't have a 17:28.440 --> 17:33.750 great big hole in the wall may be slightly different so I'm going to move the camera down and just check 17:33.790 --> 17:35.780 that hypothesis as well. 17:37.330 --> 17:44.350 So I'm just rendering here with out at the light portals and then I'll enable them and compare. 17:44.350 --> 17:48.070 And here's the final render with those light portals turned and was is finished. 17:48.070 --> 17:53.620 I'll compare the two and see if my hypothesis that facing a giant light source any weighed with the 17:53.620 --> 17:58.460 camera is going to mitigate most of the benefits of a light portal. 18:02.110 --> 18:09.250 Okay so looking at the two I can quite comfortably say at this point I think enough light is entering 18:09.250 --> 18:14.680 our scene that we don't particularly have a problem lighting it. 18:14.680 --> 18:19.560 So with that in mind I'm glad any more light portals at the moment. 18:19.570 --> 18:25.060 In my particular scene I think if I didn't have quite so many windows we might be able to see more of 18:25.090 --> 18:32.350 an affect of this whole building didn't have this great big open archway at the top as well. 18:32.500 --> 18:38.290 So I will keep the portals in mind for my particular model if it starts to get noisy I can start adding 18:38.290 --> 18:42.500 them in later and I will start adding them into the actual pieces themselves. 18:42.610 --> 18:48.470 So when I link for more highly detailed models in it will bring across the portal information as well. 18:49.360 --> 18:55.300 I'd love to see your models did using light portals of make your scene less noisy. 18:55.300 --> 18:58.600 Did it make no difference at all like it has done mine here. 18:58.630 --> 19:02.850 Please post in discussions and I will see you guys in the next lecture.