WEBVTT 1 00:00:00.400 --> 00:00:04.400 Welcome to Diffuse and Specular Materials! So in 2 00:00:04.400 --> 00:00:08.400 this video, well we need to understand these for getting 3 00:00:08.400 --> 00:00:12.400 rendering just right. We'll be looking at the two in isolation and seeing what they 4 00:00:12.400 --> 00:00:16.400 do and combining them to see the overall effect. And just 5 00:00:16.400 --> 00:00:19.966 a reminder that we are still using Blender Render! so 6 00:00:19.966 --> 00:00:22.633 Diffuse vs. Specular 7 00:00:22.633 --> 00:00:26.633 reflections! Well both are types of reflection, and 8 00:00:26.633 --> 00:00:30.633 Diffuse is essentially when light scatters, as it hits a surface, 9 00:00:30.633 --> 00:00:34.633 and Specular is a direct reflection of the light 10 00:00:34.633 --> 00:00:38.633 onto the viewer. Materials, in the real world, are often 11 00:00:38.633 --> 00:00:42.533 a mix of the two. So a bit of physics for you all, 12 00:00:43.000 --> 00:00:47.000 the Law of Reflection! So we've got the blue arrow on 13 00:00:47.000 --> 00:00:51.000 the left, and that's the light coming in the angle of incidence of 14 00:00:51.000 --> 00:00:55.000 of that light beam coming in. This is just a tiny photon hitting 15 00:00:55.000 --> 00:00:59.000 this surface, equals the angle of reflection, that's the 16 00:00:59.000 --> 00:01:03.000 light coming out of it. So that's the basic Law of 17 00:01:03.000 --> 00:01:07.000 Reflection, and let's look at that in a bit more detail. So 18 00:01:07.766 --> 00:01:11.766 Specular Reflection looks kind of like this! So a highly Specular 19 00:01:11.766 --> 00:01:15.766 surface, almost 100% in this case, if I've got my angles and 20 00:01:15.766 --> 00:01:19.766 everything right, the light beam comes in and comes out in exactly the same way 21 00:01:19.766 --> 00:01:23.766 it came in, and that would produce what you would see 22 00:01:23.766 --> 00:01:27.766 like on a mirror or on a lake, a still lake 23 00:01:27.766 --> 00:01:31.766 reflecting mountains in the background. How picturesque! So that 24 00:01:31.766 --> 00:01:35.766 would be almost 100% specular reflection, where you 25 00:01:35.766 --> 00:01:39.533 get a direct reflection of whatever is coming in. 26 00:01:40.033 --> 00:01:44.033 Diffuse Reflection, however, is slightly different, because 27 00:01:44.033 --> 00:01:48.033 the real world is not all lovely, flat, and smooth, 28 00:01:48.033 --> 00:01:52.033 we end up with a lot of Diffuse Reflection. As you can see here, the light's 29 00:01:52.033 --> 00:01:56.033 coming in and going out is all over the place, so you 30 00:01:56.033 --> 00:01:57.300 don't get 31 00:01:57.300 --> 00:02:00.566 direct reflection. Just like when you look at your wall, 32 00:02:00.566 --> 00:02:04.566 right now, it's probably painted in a matte or a satin 33 00:02:04.566 --> 00:02:08.566 paint, rather than a highly glossy paint, which is more Specular, 34 00:02:08.566 --> 00:02:11.300 and then, of course, you may have mirrored walls. 35 00:02:11.300 --> 00:02:14.100 So let's hop over into 36 00:02:14.100 --> 00:02:18.100 Blender and see how these act, when using Blender Render. 37 00:02:18.666 --> 00:02:22.666 Alright, so I've opened up a new Blender file! 38 00:02:22.666 --> 00:02:26.666 I suggest you save the work that you're working on. Now, the reason why I've opened up a new one is because 39 00:02:26.666 --> 00:02:30.666 we're going to be playing about and experimenting, and we don't want to 40 00:02:30.666 --> 00:02:34.666 do that in the chess scene that we're working with, at the moment. So the first 41 00:02:34.666 --> 00:02:38.666 thing that I'm going to do is get rid of our cube that's here, because it's 42 00:02:38.666 --> 00:02:42.666 not going to show off the Diffuse vs. Specular very 43 00:02:42.666 --> 00:02:46.000 well, so I'm just going to Delete that from our scene. 44 00:02:46.000 --> 00:02:49.266 I'm then going to Add, into our scene, the 45 00:02:49.266 --> 00:02:53.266 Monkey, a bit more exciting a mesh! And 46 00:02:53.266 --> 00:02:57.266 since the light is above the monkey, just behind it, as 47 00:02:57.266 --> 00:03:01.266 we can see here, that little orange blob now, well 48 00:03:01.266 --> 00:03:05.266 we will want to orientate our monkey so at least it's 49 00:03:05.266 --> 00:03:09.266 facing that way. So I'm going to rotate it around the X axis. 50 00:03:09.266 --> 00:03:13.266 Whoah, there we go! And that 51 00:03:13.266 --> 00:03:17.266 will probably be enough, but I'm just going to rotate it around the Z, as 52 00:03:17.266 --> 00:03:21.266 well, so the face is facing the light! 53 00:03:21.266 --> 00:03:25.266 I'm going to quickly hop over into Rendered Mode, on the Viewport shading, 54 00:03:25.266 --> 00:03:29.266 just to make sure that the face is getting the right amount of light, 55 00:03:29.266 --> 00:03:33.266 and it seems it is! Now, a couple of things I want to do, that's a bit too 56 00:03:33.266 --> 00:03:37.266 low poly for me; I do want to up it, so I can really show off 57 00:03:37.266 --> 00:03:41.266 what the Specular and Diffuse shading can do. So I'm going to 58 00:03:41.266 --> 00:03:45.266 turn on Smooth Shading, initially, and see what happens, and it's still a bit jagged around 59 00:03:45.266 --> 00:03:49.266 the edge. So, as we've done in the past, I'm going to add a 60 00:03:49.266 --> 00:03:53.266 Modifier, a Sub-Surface Division Modifier, just to smooth 61 00:03:53.266 --> 00:03:57.266 this mesh out. So under the wrench, under Add Modifier. 62 00:03:57.400 --> 00:03:59.433 So we're going to Add the Modifier here, 63 00:03:59.433 --> 00:04:02.466 Subdivision Surface Modifier, under the Generate, 64 00:04:02.466 --> 00:04:05.500 second column, third one up from the bottom. 65 00:04:05.500 --> 00:04:09.500 And oops, that's done enough smoothing, I'm happy with that! I think if 66 00:04:09.500 --> 00:04:13.500 it gets any smoother, we probably won't notice if we up it even one more. 67 00:04:13.500 --> 00:04:17.500 Ah, there isn't a small difference there, but again, you get into 68 00:04:17.500 --> 00:04:21.500 diminishing returns quite quickly, so I'll probably leave that at 2, for the 69 00:04:21.500 --> 00:04:25.500 moment. So there we have our monkey! I think she's 70 00:04:25.500 --> 00:04:29.500 called Suzanne? Yes she is! Excellent! So we need to 71 00:04:29.500 --> 00:04:33.500 apply the material to that monkey there. 72 00:04:33.500 --> 00:04:37.500 So now, create a new material and just call it Test. 73 00:04:37.500 --> 00:04:41.500 So there we go! And this material, let's scroll down a little and 74 00:04:41.500 --> 00:04:45.500 have a look at the options. So we have Diffuse and Specular. We're going to be 75 00:04:45.500 --> 00:04:49.500 focusing on these two here, it's Shading, Transparency, 76 00:04:49.500 --> 00:04:53.500 Mirror, Subsurface Scattering, Strand, Options, etc. etc. 77 00:04:53.500 --> 00:04:57.500 We can go into those at a later time but not now, we really want to 78 00:04:57.500 --> 00:05:01.500 focus on just these two here, because they're going to make up most of what you're going 79 00:05:01.500 --> 00:05:05.500 to be doing, so I'm just going to hide all of that lot there. OK, so the 80 00:05:05.500 --> 00:05:09.500 intensity on both of these simply turns up their values. So if 81 00:05:09.500 --> 00:05:13.500 they're both down at 0, you probably guessed it that the 82 00:05:13.500 --> 00:05:15.233 image is completely dark and 83 00:05:15.400 --> 00:05:19.400 is not reflecting any light at all. In this case, it's absorbing 84 00:05:19.400 --> 00:05:23.400 all the possible light. The Diffuse, when we turn that up, well 85 00:05:23.400 --> 00:05:27.400 if it's all at 1 we end up with a very matte finish, so there's 86 00:05:27.400 --> 00:05:31.366 lots of diffuse reflection coming from here. So 87 00:05:31.366 --> 00:05:35.300 we have that scattering effect that we looked at earlier, so this would be 88 00:05:35.300 --> 00:05:39.300 very similar to a terra cotta pot. So if we change this 89 00:05:39.300 --> 00:05:43.300 to maybe that sort of color. There you go, ooh that's 90 00:05:43.300 --> 00:05:47.300 a bit too pink now! Very close, I was the second click. 91 00:05:47.300 --> 00:05:51.300 I'm not going to play about with this! So there we go, a sort of 92 00:05:51.300 --> 00:05:55.300 terra cotta pot! But if you were to gloss that pot, you would 93 00:05:55.300 --> 00:05:59.300 add some Specular to it, so that will give it some highlights. So we'll 94 00:05:59.300 --> 00:06:03.300 bring the specular up and see how it looks. And in this case, this is looking rather plasticky 95 00:06:03.300 --> 00:06:07.300 still, and we may need to actually change the hardness. 96 00:06:07.300 --> 00:06:11.300 So if we lower that down, you'll find that the 97 00:06:11.300 --> 00:06:15.300 highlights get more and more spread out, and if we make it really really really 98 00:06:15.300 --> 00:06:19.300 hard, it goes up to 511, we end up with these 99 00:06:19.300 --> 00:06:23.000 very fine wispy like highlights. 100 00:06:23.000 --> 00:06:26.866 So that changes the apparent hardness or 101 00:06:26.866 --> 00:06:30.866 sharpness of those reflections, and you can play about with those to your heart's content. 102 00:06:30.866 --> 00:06:34.866 Ramp, well that changes the way that the color 103 00:06:34.866 --> 00:06:38.866 is brought into the scene, and this, we can see here, enables a 104 00:06:38.866 --> 00:06:42.866 lot more options. And we're not going to go into those, at the moment either, we just need to know 105 00:06:42.866 --> 00:06:46.866 about these two items here. Now these two here, the 106 00:06:46.866 --> 00:06:50.400 Lambert and CookTorr, they're the shader types. 107 00:06:50.400 --> 00:06:53.266 So you've got five options of 108 00:06:53.266 --> 00:06:57.266 Diffuse Shader and five options of 109 00:06:57.266 --> 00:07:01.266 Specular Shader. Now, these change how the 110 00:07:01.266 --> 00:07:05.266 Diffuse and Specular Shading is worked out, and 111 00:07:05.266 --> 00:07:09.266 it does vary quite dramatically between all of these. 112 00:07:09.266 --> 00:07:13.266 Fresnel, if I'm pronouncing that correctly, as you can see here has 113 00:07:13.266 --> 00:07:17.266 changed it very very dramatically, and these are quite sensitive. 114 00:07:17.266 --> 00:07:21.266 Let's turn it up, maybe, to 1.2 and maybe that down to 2. 115 00:07:21.266 --> 00:07:25.266 So you get a very sort of chrome like effect going 116 00:07:25.266 --> 00:07:29.266 on with the Fresnal shader, going on there. The CookTorr 117 00:07:29.266 --> 00:07:33.266 on here, well if we change it we see we get much sharper. 118 00:07:33.266 --> 00:07:37.266 I'm just going to change these, now you get a completely different feel and look 119 00:07:37.266 --> 00:07:41.266 to your model, depending on which shader option you go for. Some of them will 120 00:07:41.266 --> 00:07:45.266 be very very similar. I quite like this one, the 121 00:07:45.266 --> 00:07:49.266 Warsido, or Wardiso. 122 00:07:49.266 --> 00:07:53.266 I can't [Laughs]... Ah, here we go, it's "use a Ward 123 00:07:53.266 --> 00:07:57.266 anisotropic shader". So there's lots of options 124 00:07:57.266 --> 00:08:01.266 there, and you can change these about to your hearts' content and get the 125 00:08:01.266 --> 00:08:05.266 actual end result that you want. That's gotten incredibly plastic 126 00:08:05.266 --> 00:08:07.400 here, at this point, but there we go! 127 00:08:07.400 --> 00:08:10.600 We can see that the Oren-Nayer 128 00:08:10.600 --> 00:08:14.600 gives this new option down here, Roughness, so that 129 00:08:14.600 --> 00:08:18.600 will increse I presume the aparrent roughness of a material, 130 00:08:18.600 --> 00:08:22.600 making it slightly dark, by the looks of things. Now, this is quite a smooth 131 00:08:22.600 --> 00:08:26.600 material, so I don't know whether we'd get a decent result, 132 00:08:26.600 --> 00:08:28.300 playing about with it anymore. 133 00:08:29.600 --> 00:08:31.066 Now, if we look behind the area 134 00:08:31.433 --> 00:08:35.433 where we don't get any light, at the moment. Now, this is 135 00:08:35.433 --> 00:08:39.433 again one of the things to remember with Blender Render, 136 00:08:39.433 --> 00:08:43.433 you won't get any bounce off of other objects, but you can 137 00:08:43.433 --> 00:08:47.433 fake some of that. I know we said we're not going to dip into 138 00:08:47.433 --> 00:08:51.433 the Shading or anything lower, but one of the things you can do is 139 00:08:51.433 --> 00:08:55.433 just make the material itself slightly emissive, as if it's giving off 140 00:08:55.433 --> 00:08:59.433 light. And of course, it would give off light if there was something hitting the back. 141 00:08:59.433 --> 00:09:03.433 So if you turn up the Emit value, ever so slightly, all of a 142 00:09:03.433 --> 00:09:07.433 sudden, the back is not completely dark. One or two is absolutely 143 00:09:07.433 --> 00:09:11.433 fine, and that just gives it a bit more detail in the background. 144 00:09:11.433 --> 00:09:15.433 There are other options down here, feel free to play with them. One of my favorites 145 00:09:15.433 --> 00:09:19.433 is Mirror and turning the reflectivity all the way up. Of course, 146 00:09:19.433 --> 00:09:23.433 that's reflecting, what's it reflecting? Absolutely nothing! It's reflecting 147 00:09:23.433 --> 00:09:27.433 the environment around it, but obviously, you can play with that to your hearts' 148 00:09:27.433 --> 00:09:31.133 content, perhaps pop something in an environment and turn the reflectivity up. 149 00:09:31.133 --> 00:09:35.133 OK, so to just finalize here, I've done the monkey 150 00:09:35.133 --> 00:09:39.133 Suzanne, using all five different 151 00:09:39.133 --> 00:09:43.133 Diffuse Shaders. So over here in the Outliner, I'm just going to turn them on 152 00:09:43.133 --> 00:09:47.133 one at a time. So this is, as I've said before, it's Fresnel. 153 00:09:47.133 --> 00:09:51.133 No it's not, the s is actually silent, so I presume it's frenel. 154 00:09:51.133 --> 00:09:52.366 This is what it would 155 00:09:52.366 --> 00:09:54.966 look like. If we turn Lambert on 156 00:09:54.966 --> 00:09:58.966 we can see that that is ever so slightly different, as well. 157 00:09:58.966 --> 00:10:02.966 The mini art is down here, 158 00:10:02.966 --> 00:10:06.966 let's turn on the orin, and that's up 159 00:10:06.966 --> 00:10:10.966 there, and then, finally the tune shader, and we'll just 160 00:10:10.966 --> 00:10:14.966 let that render out. And you can see that each one is drastically 161 00:10:14.966 --> 00:10:18.966 different from the last one there, completely different in their 162 00:10:18.966 --> 00:10:21.233 appearance. So it's worthwhile 163 00:10:21.233 --> 00:10:24.866 trying out the various ones to get the style that you 164 00:10:24.866 --> 00:10:26.400 want. 165 00:10:26.566 --> 00:10:30.566 Alright, a quick challenge for you guys now, a reflection challenge! 166 00:10:30.566 --> 00:10:34.566 So assuming the same lighting conditions, 167 00:10:34.566 --> 00:10:38.566 grab a pen and paper and name yourself a material that is almost 100% 168 00:10:38.566 --> 00:10:42.566 specular. Then, think about 169 00:10:42.566 --> 00:10:46.566 which materials you think have almost no specularity, that don't have 170 00:10:46.566 --> 00:10:47.900 reflections on them. 171 00:10:47.900 --> 00:10:51.033 Now, look at items around you and you will suddenly start 172 00:10:51.033 --> 00:10:55.033 noticing this detail in objects themselves. 173 00:10:55.033 --> 00:10:59.033 So pause the video now and give that a go! 174 00:10:59.033 --> 00:11:03.033 OK guys, welcome back! Well looking around what 175 00:11:03.033 --> 00:11:07.033 I had, I have my tea pot here, lovely 176 00:11:07.033 --> 00:11:11.033 reflection in there and my little Bluetooth headset, 177 00:11:11.033 --> 00:11:15.033 and they were very glossy and highly specular and 178 00:11:15.033 --> 00:11:19.033 we can clearly see reflections of the windows, amongst other 179 00:11:19.033 --> 00:11:23.033 things in those objects. So going on to a medium 180 00:11:23.033 --> 00:11:27.033 specular, well my micphone stand is sort of a satin 181 00:11:27.033 --> 00:11:31.033 finish to it and has quite clearly 182 00:11:31.033 --> 00:11:35.033 defined specularity on it, but it's not 183 00:11:35.033 --> 00:11:39.033 super reflective. The same with the toy train that I have on my 184 00:11:39.033 --> 00:11:43.033 desk, for some bizarre reason, and I notice, 185 00:11:43.033 --> 00:11:47.033 of course, there is a bit of high specularity in the wheel hubs and the 186 00:11:47.033 --> 00:11:51.033 magnet there on the front but that's fine, the rest is sort of a medium. 187 00:11:51.033 --> 00:11:55.033 Then finally, low specular, I've got an old Nexus phone, and the 188 00:11:55.033 --> 00:11:59.033 back of it is very rubberized, so it doesn't really 189 00:11:59.733 --> 00:12:03.233 reflect anything at all. In fact, in this case, 190 00:12:03.233 --> 00:12:07.233 that leading edge there is really exaggerated, because it's a light quite 191 00:12:07.233 --> 00:12:11.233 close to it. How did you guys get on? 192 00:12:11.233 --> 00:12:12.433 I hope you now get 193 00:12:12.433 --> 00:12:16.133 what Diffuse and Specular are, and I will see you 194 00:12:16.133 --> 00:12:18.866 in the next lecture!