Blender [2.8/2.9] Character Weight Paint: #1 Vertex Groups (beginner tutorial)

this is a short series on weight painting specifically weight painting as it relates to armatures and rigging or in other words setting and painting bone weights but here on cg dive i like to go a little bit more in depth in general to understand weight painting you first have to understand vertex groups so this first part is going to be very basic maybe too basic for some of you we're going to go over vertex groups and a little bit about weight paint mode then in the next part i'll give you an overview of the tools and options in weight paint mode and then we can move into actually painting bone weights and since i have a series about rigify at the end i'll also explain how to paint weights for your characters that are rigged with rigify if you want to follow along you can download this scene that i'm starting from the link will be in the description the scene is simple we have a character a rig as well that is not parented to the to the character yet and i also have a rigified rig which we'll use for the riggify section so what are vertex groups vertex groups are a way to limit the effect of some blender functions to only a part of your mesh they have many many applications for example we can make the displace modifier only deform the leg of this character we can make this character emit particles but only from its hands not from the whole body and of course when rigging a character we can define the area of influence of each bone so the shin bone only affects the shin area and the thigh bones only affects the vertices in the thigh so let's try to create a vertex group select the character the mesh and go to object data properties and you'll find the vertex groups area it should be at the top if you haven't moved these fields around if you click this plus icon you can create a vertex group so let's create three of them by clicking this plus button three times and i'm going to rename these groups a little bit the first one will be group a group d and group c these groups are still empty so we can't really use them yet we need to add vertices to them there are two main ways to do that one is through weight painting and the other is to manually assign them in edit mode okay if i click on group a i'll highlight it and that means that it is active and that means that i'm working on this group let's switch to edit mode and by the way if the end panel is not open open it and switch to item this will be important in a second when we switch to edit mode this field changed a little bit there are a couple of buttons and this weight slider which i can slide from zero to one so let's keep it to one and select one vertex at random i'm actually going to press slash to isolate the mesh and i'm going to select one vertex for example this one on the on the knee with the weight slider to 1 i'm going to click assign then i'm going to select another vertex just avoid selecting a vertex that is right next to this this first one so i'm going to select this one set the weight to 0.5 and click assign and then select another vertex that is not connected to the previous one weight to 0.2 and click assign okay now we can switch to weight paint mode you'll probably notice that the vertices where we did something where we edit weights are colored differently than the rest of the mesh the whole mesh is kind of blue so weight paint mode allows us to see the influence of the vertex group over the mesh now let's quickly set up the viewport for best visibility my mesh in object mode appear appears blue and that is because i have set up a custom viewport display color for it when we go to weight paint mode weight paint mode overlays a color gradient over your mesh that goes from from blue a blue means no influence all the way to red which means full influence or weight of one so it is best to have your mesh completely white the default color of your mesh completely white so that you can see the weight overlay as clearly as possible the settings i recommend is to keep the shading to solid you know do not use material preview because that will if you have textures on your mesh they'll be shown in the viewport and that will confuse you when you try to paint weights and then if you have custom color for your viewport display like i have you can go over here on on the additional shading options and either switch to object or single and that will give you a white color for your mesh speaking of viewport options there are a couple of additional if i switch to weight paint mode there are a couple of additional weight paint options over here for the overlays but i find the defaults work perfectly and i never really touch them so now i can more clearly see the weights that i set a minute ago the vertex where we set a weight of 1 is really red color now the one where we set a weight of zero 0.5 is kind of green and here we set a weight of 0.2 and it's it may be a little bit hard to see but it has become this light blue color so weight paint mode gives you a visual representation of your weights and it also allows you to paint the vertex weights in a way that is more visual and artistic so instead of selecting vertices and clicking a sign i can just drag my mouse over the mesh and i'll be painting my weights i'll explain weight paint mode later so for now just ignore this i'm going to press ctrl z to undo the the weight paint okay let's go back to edit mode switch to object data properties and let's look at the other buttons that we have over here if i select these two vertices where i know that i have vertex weights assigned and simply click remove then they'll be removed from my group and if we go to wait paid mo mode we can visualize that there they have been removed now the remove button doesn't care about this weight slider it will simply completely remove any vertex from your group now let's undo until i have my weights back now i'm going to click in the 3d view to deselect everything and then i'm going to click this select button and as you can see all of the vertices where we assigned weights have been selected okay so now i'm going to press a to select the whole mesh and then i'm going to press deselect and again these vertices where we assigned weights were deselected this time so these select and deselect buttons simply select or deselect all of the vertices that are included in this group which is highlighted and again the weight slider doesn't have anything to do with the selection even if your vertex has a vertex weight of 0.0 the select function will still select it and this can be very useful when you manually tweak your weights in edit mode okay what else we have these arrows here if i click them i can reorder i can change the order of my groups which can be useful sometimes but i rarely use it this little triangle you may have seen it in other parts of blender we also used it when we were working with rigify it shows a search field and this allows me to filter this list of groups so for example if i type underscore a then only my group a will be visible and that can be very useful when i have a lot of groups and finally there is this drop down menu now most of the options that you'll see here are quite advanced or they require more of a context to be explained so i'm not going to go into detail here maybe we'll have more advanced tutorial where i explain them but the one function that you may want to take a look at is this delete all groups sometimes you just want to get rid of all of your groups and then you can click this function and all groups will be gone now i'm going to press ctrl z to undo which didn't work that's interesting oh there we go i went to object mode and then i pressed ctrl z and then i got my uh groups back that was interesting i'm not sure if that's a bug or anyway um earlier i asked you to expand the end panel and switch to item and the reason for that is when i select one of these vertices that has weight assigned i'll get this vertex weights field now let's if i click another vertex that has nothing no weights then this field will disappear let's see what we have here first there's this these buttons that say all deform and other this lets you filter out only your only your weights that have to do with bones so if you click the deform option it will only show weights that have to do with bones and if you click other it will show weights that don't have to do with bones and if you click all then it will show all groups and right now we only have one group assigned to this vertex but we can have more more than one and i'll show that in a second below it we have the group which uh to which this vertex belongs and the weight so currently it is one and i can tweak this value right here in this area and if i click on it and then i can set a very very precise value so if i want this value to be 0.626 i can do that so here you can set very precise values uh same same over here actually with the assign button uh whereas weight paint mode is less precise but is more artistic and visual and fast okay there's this x button if i click it this vertex will be removed from this group so that is the same as clicking remove over here i'm going to click it and then ctrl z to undo this paste icon and the copy button can transfer weights from the active vertex to all selected to all selected ones this one should be explained in context so let's skip it for now and also i rarely use it when painting bone weights and finally there's this normalized function i think this is very important to understand so i'm going to try to explain it as best as i can this is the main reason why i created the all of these three groups so let's select one different vertex at random and set the weight to one and click assign to group a then i'm going to highlight group b and again click assign with weight to 1 and group c again assign and as you can see here in the end panel all of the groups to which this vertex belongs are shown now and now that we have more than one group i can also click these buttons here group a or b group c and that will select the group over here in the vertex groups so now we have a value of one for each of these groups so this vertex fully belongs to group a group b and group c and that is not a problem in general as i said vertex groups have many applications so for example we may want group a to control the influence of of the displaced modifier we may want group b to control the influence of particles and group c can be used for soft body simulation however when we paint bone weights we generally don't want to have this situation where a vertex belongs to many groups to more than one group and the sum of these values is not one this will make more sense later when we actually paint weights for bones but for now just understand that you can click this normalize button and that will normalize the values of these groups what that means is that based on their initial not normalized values it will assign new values the sum of which which are exactly one so in this case all values of three groups was one so the normalized values are 0.333 for each of those and the sum of that will be exactly one if you have a value of 0.5 for group a zero point 0.5 for group b and 1 for group c then when we normalize we'll get these we'll get this kind of normalized values i think you see how this works the normalized function will tweak these values proportionally and it will make it so that their sum equals exactly one okay i already said that um vertex groups can be used for many things so let's give a an example i'm going to press a and select the whole character and then select group a and remove all vertices also remove them from b and from c now for for group a let's enable x-ray mode and just select the vertices of the of one leg and click assign for group b let's just select the hands and click assign and that will be enough okay for the modifiers first i'm going to add a subdivision surface and then on top of it let's add a displace modifier now as you can see that just inflates the whole mesh i'm going to reduce the strength a bit and then for for vertex group i'm going to select group a and as you can see that limits the effect of the displays modifier on to only the leg let's reduce the influence a little bit more now if i go to edit mode i can select a little bit more of these vertices go to data object data properties set the value to let's say 0.5 click assign and let's go back to object mode and these vertices were also added to the displaced modifier but they have less influence i think it's it will be even easier to see if we enable these these displays of these display options over here let's go back to edit mode again select some more vertices go to object data properties set this to 0.25 and click assign oh yeah i have to select group a okay over here i'm going to select some these vertices wait to 0.5 and click assign now if i go to weight paint mode i can see my weights and if i start painting uh maybe if i remove the overlays it will be easily visible as soon as i paint vertex weights for group a the displaced modifier will start to this to to affect this area okay now let's remove these modifiers we don't need them there we're just here for a quick demonstration let's go to the particles tab uh create a new particle system and press play and you'll see particles coming from the whole character for viewport display i'm going to reduce their size a little bit and then on the vertex groups density i'm going to choose group b which was hence by mistake i selected some of these some of these vertices or they were added to group b but i think you can see how this particle system is controlled by the vertex group so those are two quick examples of how we can use vertex groups for stuff that is not bone weights but anyway let's move on in the next part we're going to go over the weight paint mode all of its tools and options and then we can start painting some bone weights thanks i hope you learned something and if you like this video please click like and subscribe that helps a lot

Channel: CGDive (Blender Rigging Tuts)

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Id: LPYs3pZEzPY

Length: 17min 30sec (1050 seconds)

Published: Sat Sep 12 2020