WEBVTT 00:00.000 --> 00:01.927 Hi, my name is Demeter and in this video I would 00:01.939 --> 00:04.040 like to give you an introduction on weight painting, 00:04.260 --> 00:05.986 also called skinning in other software. The most 00:05.998 --> 00:07.880 common use for weight painting is to make characters 00:07.881 --> 00:09.766 deform during animation, and that is probably 00:09.778 --> 00:11.760 why you clicked on this video. Some people also 00:11.761 --> 00:13.279 use the terms weight painting and rigging 00:13.303 --> 00:14.820 interchangeably, but to me rigging means 00:14.821 --> 00:16.842 creating bones, constraints, and drivers to make 00:16.854 --> 00:18.760 a control rig, which is not the focus of this 00:18.761 --> 00:20.799 video. Weight painting usually happens after 00:20.811 --> 00:23.000 you already have a control rig, but technically 00:23.001 --> 00:24.733 nothing is stopping you from doing it the 00:24.745 --> 00:26.660 other way around. So what is weight painting? 00:26.661 --> 00:28.977 Weight painting is the altering of vertex groups 00:28.989 --> 00:31.220 in a faster intuitive way, so before we go any 00:31.221 --> 00:33.012 further than that, let's have a crash course on 00:33.024 --> 00:34.980 vertex groups. Delete everything beside the default 00:34.981 --> 00:37.818 cube, then select the cube, go on the data panel 00:37.830 --> 00:40.500 in the properties editor, and I can add a new 00:40.501 --> 00:42.501 vertex group with this plus button, and I can 00:42.513 --> 00:44.480 double click on it to change the name. Every 00:44.481 --> 00:46.397 mesh object in Blender can have any number of 00:46.409 --> 00:48.380 vertex groups, but as you can see, their names 00:48.381 --> 00:50.409 have to be unique, so two vertex groups on 00:50.433 --> 00:52.460 the same object cannot have the same name. 00:52.840 --> 00:55.165 If I switch to edit mode, the UI changes a bit and 00:55.177 --> 00:57.420 now allows me to assign or remove weight values. 00:57.820 --> 00:59.786 If you open the end panel and go to item, 00:59.798 --> 01:01.920 well, you'll see nothing relevant because we 01:01.921 --> 01:03.725 haven't assigned any vertices to any groups 01:03.737 --> 01:05.680 yet, so I'm going to select my hello group and 01:05.681 --> 01:07.517 click assign. Still, what I want to show you 01:07.529 --> 01:11.132 is not here because we need to have an active vertex, so I'm just going to select a 01:11.144 --> 01:13.240 vertex, and now you can see there is a vertex 01:13.241 --> 01:14.867 weights panel, and this shows the weights 01:14.879 --> 01:16.836 assigned to the active vertex. So as you can see, 01:16.860 --> 01:18.868 the hello vertex group has a weight of 1.0. 01:18.880 --> 01:21.040 Because of the terminology, you might think of 01:21.041 --> 01:23.106 group assignments as binary. Either a vertex is 01:23.118 --> 01:25.240 in a group or it isn't, but that's not the case. 01:25.560 --> 01:27.468 Each vertex group can associate a value between 01:27.480 --> 01:29.440 0 and 1 with any number of vertices on the mesh. 01:29.760 --> 01:34.620 For example, if I were to select every vertex again and set this weight value to 0.6 01:34.621 --> 01:38.740 and then hit assign, all of those vertices would have a weight of 0.6, 01:39.240 --> 01:43.020 and this will of course have a significance once we start using vertex groups to deform 01:43.021 --> 01:47.820 our mesh. So let's go ahead and do that. Let's go back into object mode and add an 01:47.821 --> 01:50.863 armature with a single bone. I will go in viewport 01:50.875 --> 01:53.440 display in front so you can see it through 01:53.441 --> 01:58.180 everything else. And so in order to deform a mesh using an armature, you need to add 01:58.181 --> 02:02.440 an armature modifier and then select that armature. Now you'll notice of course that 02:02.441 --> 02:04.247 if you just select the armature and move it, 02:04.259 --> 02:06.200 that's not going to move the cube. And in fact, 02:06.201 --> 02:07.888 even if you go into pose mode and move the 02:07.900 --> 02:09.761 bone, that's still not going to move the cube. 02:10.020 --> 02:12.960 Unfortunately, the armature modifier can't read our minds, so we need to make sure 02:12.961 --> 02:14.900 that there is a clear association between the 02:14.912 --> 02:16.820 vertex groups and the bones. This is done by 02:16.821 --> 02:18.727 ensuring that the bone name and the vertex 02:18.739 --> 02:20.840 group name are in exact match. So this default 02:20.841 --> 02:23.139 bone is of course just called bone with a 02:23.151 --> 02:25.800 capital B. Let's go and rename our vertex group 02:25.801 --> 02:31.380 accordingly to bone. And now if we move the bone in pose mode, it will move our cube. 02:32.340 --> 02:34.128 Note though that if you move the armature in 02:34.140 --> 02:35.980 object mode, it's still not going to move the 02:35.981 --> 02:38.121 cube. If you want to do that, you would have to 02:38.133 --> 02:40.240 parent the cube to the armature using control. 02:40.780 --> 02:44.940 P. Although doing this is not necessary, it is standard and you can even do these two 02:44.941 --> 02:46.829 things in one step. That is, parenting the cube 02:46.841 --> 02:48.821 to the armature and adding the armature modifier. 02:49.340 --> 02:51.634 You can also undo that in one step. So if I 02:51.646 --> 02:54.220 select the cube and I hit alt P to clear parent, 02:54.760 --> 02:58.440 notice that it automatically removes the armature modifier for me. So now if I go 02:58.441 --> 03:01.641 and with the cube selected, shift select the armature and press control P again, 03:01.820 --> 03:03.558 but this time I choose armature deform, it's 03:03.570 --> 03:05.440 going to parent the cube to the armature object 03:05.441 --> 03:07.565 as well as add this modifier for me. Now, you 03:07.577 --> 03:09.760 might have noticed something unexpected when I 03:09.761 --> 03:12.065 was moving this bone in pose mode, which is 03:12.077 --> 03:14.500 that even though we assigned a weight of 0.6, 03:14.501 --> 03:18.140 this cube seems to be following completely, even though you probably expected it to be 03:18.141 --> 03:20.486 following only 60% of this bone's transformations. 03:20.498 --> 03:22.760 This is because the armature modifier normalizes 03:22.761 --> 03:24.785 vertex weights that are used for the deformation 03:24.797 --> 03:26.620 before applying set deformation. To help me 03:26.621 --> 03:28.469 explain what I mean by normalization, let's do 03:28.481 --> 03:30.260 a couple of things. First, let's add another 03:30.261 --> 03:33.527 bone to this armature. I will duplicate this 03:33.539 --> 03:37.040 one and I'll call this other. Then let's create 03:37.041 --> 03:40.293 a vertex group for it and assign a value of 03:40.305 --> 03:43.720 1 for all vertices, as well as assign a value 03:43.721 --> 03:47.129 of 1 for the original vertex group. So now, just 03:47.141 --> 03:50.560 to double check in this panel, for all vertices, 03:51.020 --> 03:52.774 both groups are assigned 1.0. Now if we go 03:52.786 --> 03:54.720 back and try to move these bones in pose mode, 03:55.080 --> 03:56.808 you see that each bone appears to be moving 03:56.820 --> 03:58.640 the cube by about half of its transformation. 03:59.220 --> 04:03.980 So if I were to move this bone by 6 units on the x-axis, it looks like the cube has 04:03.981 --> 04:08.620 moved 3 units. Now, you might be catching on to what's going on here. Even though the 04:08.621 --> 04:10.735 weights of each bone is 1.0, the armature 04:10.747 --> 04:13.080 modifier sees the normalized values, that is, 04:13.081 --> 04:15.201 as if each weight on each vertex was divided 04:15.213 --> 04:17.200 by the sum of all weights on that vertex. 04:17.740 --> 04:21.900 So in this case, 1 plus 1 is 2. That's the sum of all weights on a given vertex. 04:22.340 --> 04:24.869 So for both vertex groups, 1 gets divided by 04:24.881 --> 04:27.480 2 and you're left with 0.5, meaning each bone 04:27.481 --> 04:29.289 will deform the cube by half of its movement. 04:29.301 --> 04:31.201 Now if you think back to what happened earlier, 04:31.300 --> 04:35.960 when we had a vertex weight of 0.6 and nothing else, the sum of all weights was 0.6. 04:36.180 --> 04:40.520 So 0.6 was divided by 0.6, giving us 1. And that's why the cube followed the. 04:41.580 --> 04:43.699 60% of the way. I hope this is at least starting 04:43.711 --> 04:45.620 to make sense, because I think it is rather 04:45.621 --> 04:47.379 important. Of course if you do a lot of maths 04:47.391 --> 04:49.160 in your daily life, you might be rolling your 04:49.161 --> 04:52.520 eyes by this point, because this is very obvious to you. But it's understandable to 04:52.521 --> 04:55.500 be confused, because there is a disconnect between the numbers that you see here in 04:55.501 --> 04:59.180 the end panel versus the deformation that you see when you move the bones. Also when 04:59.181 --> 05:02.660 you enter weight pain mode, it commonly causes confusion that even though a bone's 05:02.661 --> 05:06.260 influence is red, which represents the maximum, the mesh is still not necessarily 05:06.261 --> 05:09.760 moving 1 to 1 with the bone, which is the case here. The good news is that there 05:09.761 --> 05:13.000 are ways to avoid this confusion. For starters, there is a Normalize All 05:13.001 --> 05:16.440 operator, which lets you normalize your vertex groups. Make sure you don't 05:16.441 --> 05:19.521 mistake this for the Normalize operator, which has a much more niche purpose. 05:20.060 --> 05:23.180 So let's see what happens if you do Normalize All. Well, that's probably not 05:23.181 --> 05:26.240 what you expected, because one of the weights just turned into 1, and the other 05:26.241 --> 05:29.300 turned into 0. This is because of a rather unfortunate default parameter of 05:29.301 --> 05:32.700 this operator. If you go in the operator settings, you'll see that Lock 05:32.701 --> 05:35.700 Active is enabled by default, which completely defeats our purpose, so 05:35.701 --> 05:38.820 untick that. And now we get the result that we expected. The two weights 05:38.821 --> 05:42.580 are now 0.5 and 0.5, which matches the deformation that you see when you move 05:42.581 --> 05:45.520 the bones in pose mode. The other important feature that lets us deal with 05:45.521 --> 05:48.020 this is Auto-Normalize, which will normalize your weights every time you 05:48.021 --> 05:50.480 make a stroke while in weight pain mode. But let's not get ahead of 05:50.481 --> 05:53.960 ourselves. First off, how do we even enter weight pain mode? You can of 05:53.961 --> 05:56.460 course simply enter weight pain mode from the Object Mode drop down menu 05:56.461 --> 05:59.060 like I just did, but when working with an armature you probably want to 05:59.061 --> 06:01.560 be able to select the bones, which would allow you to quickly switch 06:01.561 --> 06:04.180 between the relevant vertex groups. But as you can see, that's not working 06:04.181 --> 06:06.880 right now. In fact, I can't even so much as select the armature object. 06:06.881 --> 06:10.900 There's two ways around this. One is to go into Edit, Lock Object Modes, and 06:10.901 --> 06:14.520 disable this option, which will allow me to select the armature object, then I 06:14.521 --> 06:17.700 can go into pose mode and go back to my cube. Alternatively, if you don't 06:17.701 --> 06:20.480 want to do that, the way you want to enter weight pain mode is that you 06:20.481 --> 06:23.840 first select the armature, then you shift select the cube, and then you 06:23.841 --> 06:26.560 enter weight pain mode. And now you can select individual bones, which 06:26.561 --> 06:29.521 will also activate their corresponding vertex groups, as you can see here. 06:30.780 --> 06:33.580 Although these two vertex groups happen to be identical at the moment, 06:33.740 --> 06:36.140 but before we start weight painting, I would like to apply a subdivision 06:36.141 --> 06:39.060 modifier on this cube, so we have some more vertices to play with. So I'm 06:39.061 --> 06:42.860 going to go back to object mode, press Ctrl 2 on the cube, and then hit 06:42.861 --> 06:47.060 apply on this subdivision modifier. Also note that selecting bones will 06:47.061 --> 06:50.700 only work if this armature modifier is present. If you remove it, you 06:50.701 --> 06:52.940 won't be able to select bones no matter what you do. So let's undo 06:52.941 --> 06:55.580 that. At this point, you can forget about a lot of the UI that I've 06:55.581 --> 06:58.460 shown you so far. You will no longer need to worry about the vertex 06:58.461 --> 07:01.540 weights panel, nor the vertex group lists, or adding vertex groups 07:01.541 --> 07:04.220 manually. And to show you why you don't need to worry about it, let's 07:04.221 --> 07:07.100 delete all the vertex groups and then go back to weight paint mode. 07:07.720 --> 07:10.080 Now just select a bone of your choice and left click anywhere on the 07:10.081 --> 07:13.700 mesh. As you can see, the vertices inside the brush circle have all 07:13.701 --> 07:16.640 snapped over to this bone called bone, and its vertex group got 07:16.641 --> 07:19.380 automatically created. And if I try moving this bone, all those 07:19.381 --> 07:21.900 vertices are going to move with it. And if I reset that bone to its 07:21.901 --> 07:24.600 original position, then our sphere looks like a sphere again. 07:25.640 --> 07:28.080 And this is what I meant in the very beginning of the video when I 07:28.081 --> 07:30.380 said weight painting is the offering of vertex groups in a fast 07:30.381 --> 07:33.320 and intuitive way. Painting with brush strokes is a lot faster and 07:33.321 --> 07:36.400 intuitive compared to assigning weights manually vertex by vertex. 07:36.620 --> 07:38.880 As you can probably tell, the values of weights are represented 07:38.881 --> 07:41.880 by colors. Where blue means zero, red means one, and there's 07:41.881 --> 07:44.860 shades of aqua, green and yellow in between. You can customize 07:44.861 --> 07:48.720 these colors under edit, preferences, editing, weight paint, 07:48.920 --> 07:51.540 use custom colors. But I recommend you only do that if you are 07:51.541 --> 07:54.060 color blind, and for example, have a hard time seeing the 07:54.061 --> 07:57.400 difference between the yellow of a 0.8 versus the red of a 07:57.401 --> 08:00.920 1.0, because then you're going to have a bad time. But actually 08:00.921 --> 08:03.960 turns out Blender itself is quite color blind. What I mean by 08:03.961 --> 08:06.580 that is by default, there is no distinction between an assigned 08:06.581 --> 08:09.660 weight of zero versus no assigned weight at all, which I think 08:09.661 --> 08:12.020 is a bad thing, and I will explain why when I talk about 08:12.021 --> 08:14.940 auto normalize. But to fix this, go in the overlay settings 08:14.941 --> 08:18.080 and set the zero weights option to active. This way, 08:18.220 --> 08:20.520 weights with the value of zero will still be blue, but 08:20.521 --> 08:22.880 when a vertex is not assigned to a group at all, it will 08:22.881 --> 08:25.560 be black. There is no downside to turning this option on, so 08:25.561 --> 08:27.361 please do. It can save you a lot of headache. 08:27.620 --> 08:29.540 All right, I think this is a good time to end the first 08:29.541 --> 08:31.760 video. If a lot of the information here was new to you, 08:31.880 --> 08:33.340 please take some time to play around with what you've 08:33.341 --> 08:35.660 learned so far and digest. Although weight painting will 08:35.661 --> 08:37.560 never be the most thrilling thing you can learn in 08:37.561 --> 08:40.480 Blender, this was definitely the boring theory part. In 08:40.481 --> 08:42.200 the next video, we will start weight painting an actual 08:42.201 --> 08:45.941 character, looking at the brushes settings and more. See you then.