WEBVTT 1 00:00:00.000 --> 00:00:02.833 Hello everybody 2 00:00:02.833 --> 00:00:06.833 and welcome back, it's Ben here with you now! We're going to talk about Coordinate 3 00:00:06.833 --> 00:00:10.833 Systems & Exporting! Before we do, I talk a little bit faster than Mikey, 4 00:00:10.833 --> 00:00:14.833 so you may want to go back to the beginning of the course and look at your video controls 5 00:00:14.833 --> 00:00:18.833 lecture, where you can choose a different speed if you want to. 6 00:00:18.833 --> 00:00:22.833 Also, of course, I'm far more charismatic and handsome than him, not that you could tell that on a 7 00:00:22.833 --> 00:00:26.833 video. [Laughs] So here we're going to be looking at the end result of your model 8 00:00:26.833 --> 00:00:30.833 and what we're likely to do with it. I'm going to show you a useful export checklist. 9 00:00:30.833 --> 00:00:34.833 I'm going to introduce you to left and right-handed coordinate systems. 10 00:00:34.833 --> 00:00:38.833 I'm going to be demonstrating an import into Unity, but you don't need to have 11 00:00:38.833 --> 00:00:42.833 Unity, it's a game engine. You don't need to have it installed, you just need to have a look at how these 12 00:00:42.833 --> 00:00:46.833 models end up over there. And I'm going to give you a little challenge, to think 13 00:00:46.833 --> 00:00:50.833 about where you want to first export to. So let's start by just talking about handedness. 14 00:00:50.833 --> 00:00:54.833 So get your fingers out and hands up in front of you, and have a think about what's on the screen 15 00:00:54.833 --> 00:00:58.833 there. This is borrowed from Wikipedia. Thank you very much to the chap who drew it, a very pretty diagram. 16 00:00:58.833 --> 00:01:02.833 So a right-handed coordinate system is one where you start with your thumb 17 00:01:02.833 --> 00:01:06.833 down the X axis. Your next finger's along the Y and then your next finger 18 00:01:06.833 --> 00:01:10.833 is Z. And that's completely different to a system where the 19 00:01:10.833 --> 00:01:14.833 left thumb is X, the next finger is Y, and then the middle finger is Z. 20 00:01:14.833 --> 00:01:18.833 And they are mirror images of one another but you cannot rotate one 21 00:01:18.833 --> 00:01:22.833 to become the other, it's just impossible if you try it, you'll see that they're just, just different. 22 00:01:22.833 --> 00:01:26.833 OK, so a quick challenge for you! I want you to go over 23 00:01:26.833 --> 00:01:30.833 into Blender, which is here, and look at the many axes 24 00:01:30.833 --> 00:01:34.833 that's down at the bottom-left of Blender there, and I want you to answer a very simple question, 25 00:01:34.833 --> 00:01:38.833 is Blender right or left handed? Use that mini axes and the previous slide. 26 00:01:38.833 --> 00:01:42.833 Write down your answer, no cheating. No Wikipedia-ing or no Google-ing for 27 00:01:42.833 --> 00:01:46.833 is Blender right or left handed. I just want you to look at that slide and work out for yourself 28 00:01:46.833 --> 00:01:50.833 and lots of twisting of your wrist, try not to break anything, whether it's left or right-handed. So 29 00:01:50.833 --> 00:01:54.833 go ahead, write that down now, and we'll see you in just a sec. 30 00:01:54.833 --> 00:01:58.833 Cool welcome back! So if we look here in Blender you 31 00:01:58.833 --> 00:02:02.833 stick your thumb along the X axis, the way I've got it defined. Your next finger 32 00:02:02.833 --> 00:02:06.833 is along the Y axis, which is really really awkward, and 33 00:02:06.833 --> 00:02:10.833 your next finger goes down the Z axis. And you'll find if you're trying to use your left hand now that not only are you in a 34 00:02:10.833 --> 00:02:14.833 very strange position but that it just doesn't work, because Z is pointing in the wrong direction. 35 00:02:14.833 --> 00:02:18.833 So Blender uses a right-handed coordinate system. You put your right thumb 36 00:02:18.833 --> 00:02:22.833 along the X axis, you put your middle finger along the Y axis, 37 00:02:22.833 --> 00:02:26.833 and then, you'll find, if you're lucky, that the Z axis 38 00:02:26.833 --> 00:02:30.833 will actually be the third finger. OK, so Blender uses 39 00:02:30.833 --> 00:02:34.833 a right-hand coordinate system. Not the case with Unity, we're going to be 40 00:02:34.833 --> 00:02:38.833 demonstrating it actually uses a completely different coordinate system. 41 00:02:38.833 --> 00:02:42.833 So here's our model in Blender, and let's 42 00:02:42.833 --> 00:02:46.833 just take a look at the Hierarchy. What have we got? We've got several things, which we don't really care 43 00:02:46.833 --> 00:02:50.833 about now, but most importantly we have three models in here a Big Pyramid, a Pyramid, 44 00:02:50.833 --> 00:02:54.833 and a Small Pyramid. Now only the 45 00:02:54.833 --> 00:02:58.833 Pyramid, I believe, is at the Origin in this thing. It's only that that's at 46 00:02:58.833 --> 00:03:02.833 (0, 0, 0). The other guys are not at (0, 0, 0), they're offset from the 47 00:03:02.833 --> 00:03:06.833 Origin. So that's one thing to notice. The other thing to notice in Blender is that Z is 48 00:03:06.833 --> 00:03:10.833 upwards, so upwards by default is Z, alright. 49 00:03:10.833 --> 00:03:14.833 OK so what does this look like in Unity? Well you don't need to know the details of how you get 50 00:03:14.833 --> 00:03:18.833 this guy, this model into Unity, but let me just go over to 51 00:03:18.833 --> 00:03:22.833 Unity now and open up this model and see what it looks like. So 52 00:03:23.233 --> 00:03:27.233 here I am in Unity 3D. Again, you don't need to load Unity, you just need to look at 53 00:03:27.233 --> 00:03:31.233 what I'm showing you here. So I have imported the Mayan Pyramid, and 54 00:03:31.233 --> 00:03:35.233 if we click that tray to expend it, you'll see that it's got lots of little components that 55 00:03:35.233 --> 00:03:39.233 come across from Blender automatically. You've got the pyramids themselves here, which 56 00:03:39.233 --> 00:03:43.233 are the composed models which consist of the scale that you 57 00:03:43.233 --> 00:03:47.233 set over in Blender. Like this Pyramid, remember, was 10 by 10 by 58 00:03:47.233 --> 00:03:51.233 1, and also the materials, they're all just using no materials. We haven't 59 00:03:51.233 --> 00:03:55.233 introduced materials in the course yet. But also just their plain meshes here, and it'll 60 00:03:55.233 --> 00:03:59.233 even tell you how many triangles they've got and things. Alright, so that's what you get over in Unity! 61 00:03:59.233 --> 00:04:03.233 Now one good thing is that Unity is smart enough to know that, actually 62 00:04:03.233 --> 00:04:07.233 Unity uses Y for upwards, whereas Blender was using Z for upwards, 63 00:04:07.233 --> 00:04:11.233 so it actually does turn the things on their sides. Take a look at Unity's coordinate system, 64 00:04:11.233 --> 00:04:15.233 and again, with reference to that other slide, just work out for yourself is this left or 65 00:04:15.233 --> 00:04:19.233 right-handed. Well as you try and maybe try your right hand 66 00:04:19.233 --> 00:04:23.233 down the X and then the next finger, then your right hand goes up the Y and you try 67 00:04:23.233 --> 00:04:27.233 and get the Z working things don't work right. So actually, Unity is a 68 00:04:27.233 --> 00:04:31.233 left-handed system, so it's actually completely the opposite to Blender. Most of the time that won't 69 00:04:31.233 --> 00:04:35.233 cause you a problem, but they are mirror images and you can't make a straight rotation from 70 00:04:35.233 --> 00:04:39.233 one to the other. So that's an example of one of the things you need to consider. 71 00:04:39.233 --> 00:04:43.233 The other thing is, let's think about how your work's been organized. We've actually put three models into 72 00:04:43.233 --> 00:04:47.233 the same model here, effectively, and you wouldn't normally do that. 73 00:04:47.233 --> 00:04:51.233 The Mayan Pyramid itself... Which one is this, the big one? 74 00:04:51.233 --> 00:04:55.233 The one called Pyramid is sitting nicely in Unity at the 75 00:04:55.233 --> 00:04:59.233 Origin, and the other thing that's good is, it's sitting on the floor. So that model, 76 00:04:59.233 --> 00:05:03.233 if you like, that sub-model is setup very nicely. We would want to 77 00:05:03.233 --> 00:05:07.233 consider whether the thing that you're exporting to can handle the scaling. 78 00:05:07.233 --> 00:05:11.233 OK, here in Unity and more importantly for you guys over in Blender, 79 00:05:11.233 --> 00:05:15.233 this guy is scaled. Remember that you set a scale? Where is it over here? 80 00:05:15.233 --> 00:05:19.233 There, X, 81 00:05:19.233 --> 00:05:23.233 Y, Z. We have a 10, 10, 1 scale. Now it happens that it 82 00:05:23.233 --> 00:05:27.233 talks to Unity, and Unity understands that, and it scales it properly. But look at these mesh previews, 83 00:05:27.233 --> 00:05:31.233 you see how distorted they are? The raw meshes actually look like that behind the scenes, and 84 00:05:31.233 --> 00:05:35.233 they are rescaled in Blender and Unity is rescaling them for us. Your 85 00:05:35.233 --> 00:05:39.233 3D printer, for example, may not be so kind to you. So you may need to 86 00:05:39.233 --> 00:05:43.233 think very carefully, with the next model you build, about whether you want to be scaling the whole 87 00:05:43.233 --> 00:05:47.233 model or not, because you might find, if you try and 3D print this guy, that it comes 88 00:05:47.233 --> 00:05:51.233 out a bit long and thin. So that's his considerations, it's the scaling. 89 00:05:51.233 --> 00:05:55.233 The other consideration is where you put the Origin. Now when Mikey set this up 90 00:05:55.233 --> 00:05:59.233 with you, he put the Origin beautifully in the middle of this pyramid, so that means that it sits 91 00:05:59.233 --> 00:06:03.233 in Unity's Origin, and it means, in your 3D printer that it's going to actually print in the middle of 92 00:06:03.233 --> 00:06:07.233 the printing bay. The other two pyramids wouldn't be so lucky. 93 00:06:07.233 --> 00:06:11.233 [Laughs] So generally speaking moving forward, for instance, when we create 94 00:06:11.233 --> 00:06:15.233 the bowling ball and the bowling pin, we would create separate blend files for those. 95 00:06:15.233 --> 00:06:19.233 We wouldn't put three different models in the same thing, we've done it this way for simplicity, but 96 00:06:19.233 --> 00:06:23.233 moving forward you'd have one blend file per model you want to create. 97 00:06:23.233 --> 00:06:27.233 You may put subelements of your model, like you might decide to separate at the top 98 00:06:27.233 --> 00:06:31.233 of the pyramid as separate components here, but they wouldn't be all in 99 00:06:31.233 --> 00:06:35.233 one. OK, so let's take a look at my export checklist I've made 100 00:06:35.233 --> 00:06:39.233 for you. Here are some questions you need to ask yourself when you are 101 00:06:39.233 --> 00:06:43.233 starting your project, actually. From the next project, we want to start thinking about these questions. 102 00:06:43.233 --> 00:06:47.233 In your target platform, what axis is up? For instance, 103 00:06:47.233 --> 00:06:51.233 in Blender it's Z and in Unity it's Y. What about the handedness of the coordinate 104 00:06:51.233 --> 00:06:55.233 system? It doesn't matter yet but with some more complex models and some animations later, it may start 105 00:06:55.233 --> 00:06:59.233 to make a difference. So are you dealing with a left-handed coordinate system, like Unity, or a right-handed 106 00:06:59.233 --> 00:07:03.233 coordinate system, which is Blender? Does the scale you set in Blender 107 00:07:03.233 --> 00:07:07.233 come through to the system you're targeting? In Unity it does. 108 00:07:07.233 --> 00:07:11.233 Maybe your 3D printer doesn't? You need to know the answer to that or test it really early on with a 109 00:07:11.233 --> 00:07:15.233 really simple model. Maybe just scale a cube and see how it works. Does the 110 00:07:15.233 --> 00:07:19.233 model have an appropriate Origin? So the pyramid in the 111 00:07:19.233 --> 00:07:23.233 center is centered perfect. The other ones are offset. If over in Unity, let me 112 00:07:23.233 --> 00:07:27.233 just show you the impact of that. If over in Unity I decide to break up 113 00:07:27.233 --> 00:07:31.233 these guys, these models, and make separate models out of say this Big Pyramid, 114 00:07:31.233 --> 00:07:35.233 this guy, and I make him down there as a separate model and delete what I had, look what 115 00:07:35.233 --> 00:07:39.233 happens when I put the Big Pyramid in! In Unity it's not at the Origin! 116 00:07:39.233 --> 00:07:43.233 This is not Unity's Origin, it's offset where it was in the 117 00:07:43.233 --> 00:07:47.233 previous scene, which is out here. This is the Origin, this 118 00:07:47.233 --> 00:07:51.233 pyramid at the bottom, and this guy is off on a limb. So be careful of that, because 119 00:07:51.233 --> 00:07:55.233 baked into this Big Pyramid is an offset. OK so you want your 120 00:07:55.233 --> 00:07:59.233 models to be centered. Are the meshes grouped appropriately? 121 00:07:59.233 --> 00:08:03.233 That's where I was talking about, you wouldn't put all three of those pyramids typically in one file, you may put 122 00:08:03.233 --> 00:08:07.233 the components of a Pyramid under one file. And 123 00:08:07.233 --> 00:08:11.233 is the model closed? Hmmm? How about the base? Well that becomes important in 3D printing, 124 00:08:11.233 --> 00:08:15.233 as we'll see later. But one thing that's super easy to forget is the base. 125 00:08:15.233 --> 00:08:19.233 Let's take a look at this guy in Unity! Does he have a bottom? Yes, we have 126 00:08:19.233 --> 00:08:23.233 bottoms, that's good. And it's a closed model, that's important in printing, but it's also important 127 00:08:23.233 --> 00:08:27.233 if your character in a game, for instance, ever takes a look from the bottom. Why? Well remember 128 00:08:27.233 --> 00:08:31.233 Mikey talked about normals and how important they were? Well game engines, 129 00:08:31.233 --> 00:08:35.233 for one, do something called Backface Culling. Ooh, you've seen that when you've played a game, you go 130 00:08:35.233 --> 00:08:39.233 inside. Look the pyramid I'm in is completely invisible to me, or at lest the faces I'm 131 00:08:39.233 --> 00:08:43.233 looking at the back of are. If I come up and look down the stairs I can see them, but I 132 00:08:43.233 --> 00:08:47.233 can't see those stairs from below, the pyramid disappears. So it's a really 133 00:08:47.233 --> 00:08:51.233 thin shell, and that's giving the illusion of a solid pyramid from the 134 00:08:51.233 --> 00:08:55.233 outside, because we have and Mikey has diligently pushed all your normals outwards. 135 00:08:55.233 --> 00:08:59.233 But that's really important that your normals are facing outwards, otherwise things will just disappear. 136 00:08:59.233 --> 00:09:03.233 So that's it, that is the checklist of things 137 00:09:03.233 --> 00:09:07.233 that you want to consider. What I want you to do now is think about where you want to export your next model to. 138 00:09:07.233 --> 00:09:11.233 Are you into 3D printing? Are you into games? Are you into Unity? I don't know. 139 00:09:11.233 --> 00:09:15.233 Write the answers to the export checklist, from the previous slide, down. Do some research for your target 140 00:09:15.233 --> 00:09:19.233 platform, and then, why not share the answers or any questions you may have in the community. 141 00:09:19.233 --> 00:09:23.233 And start getting the conversation going, so that from now, moving forward, 142 00:09:23.233 --> 00:09:27.233 you can start even from the very beginning of your modeling exercise thinking 143 00:09:27.233 --> 00:09:31.233 about how it's going to end up. So thanks for listening and we'll 144 00:09:31.233 --> 00:09:33.800 see you soon!