Tutorial: Rigging an IK Spline Back in Maya

welcome back everyone Jason Baskin here for another quick rigging tutorial in this lesson we'll cover the process of setting up an AI K spline style back for our character the setup we're going to do today is a pretty simple one but it's a good foundation for a lot of character back setups so we're going to begin by switching to the side view and then we're going to grab the joint creation tool either from the shelf or from the skeleton menu and I'm going to place some joints right along the centerline of the character's back for a more realistic character I'd probably push these joints closer to where they actually would exist for the skeleton but I want this character to have a little bit more of a cartoony range so placing the joints in the center is going to help give us that I'm going to start here at the bottom and create the first couple joints especially really close to each other and there's a couple reasons for this one's that the lower part of the back is going to be the most flexible part but I'm also going to begin the eye case spline one joint up from the root so you'll see that that extra joint is actually pretty helpful so I'll finish off with maybe seven or eight joints and you can see that I've created them here in the outliner and then I'm going to rename the joints and we'll add the eye case fly and solver so I'll rename them now alright so I've gone ahead and renamed the joints you can see that the first joint I named root and all the other joints are just sequentially numbered back joints next I'm going to add an eye K spline solver the eye case blind solver allows you to pose a joint chain based on the shape of a guide curve that can be created manually or automatically so I'm going to click on this tool and this joint can also be found here in the skeleton menu so I'm going to go to the options so that I can reset the tool and I really want to use all the default options but I'm going to turn the auto parent curve option off next I'm going to zoom in and I'm going to click the first back joint of my joint chain and then the last back joint of the joint chain so again I'm not attaching this to the root but I'm beginning with the back joints and going all the way from back one to back seven and if we hide our mesh and our skeleton we'll see that we've actually got a curve here if I go into component mode and modify the shape of the curve you'll notice that the joints follow along and so we're going to use this as the basis for our characters back setup now the animator is not going to want to go in and get into component mode to modify the back curve so we're going to have to control this in another way and the way that we're going to do that is to create something called a cluster which essentially lets you control components with a transform just as though they were their own separate objects so again I'm going to turn the joints off and I'm going to make sure I'm in component mode again by right-clicking over the curve choosing control vertex and selecting a couple of vertices I'm going to select the top two vertices and create a cluster by going to create deformers cluster and you should see at the letter C appear which indicates that a cluster is now present the cluster handle can be selected and modified here through the channel box in order to shape the curve so we're going to do the same thing with the bottom two control vertices again select the curve right click over it and choose control vertex go to create deformers and choose cluster you want to make sure that each cluster has two unique vertices so you don't want to have overlap of the ownership of the vertices between these two clusters so the bottom cluster here we'll call lower back cluster and the top cluster we'll call upper back cluster I'm also going to rename some of these elements this is going to be my ika back curve and this is going to be my back I K so let's turn our joints back on and if we select these clusters we could actually go ahead and begin shaping and animating the character using them but again animators are used to a certain type of animation control which is typically curves so we're going to control these back clusters by parenting them beneath a couple of control curves so we're going to go to our curves shelf make sure that interactive creation is turned off and then we're going to select a circle and just drag that circle up holding down the V key so that it snaps into the position of the root joint and I'm going to scale this up a bit as well and then I'm going to name this lower back control and I'm going to make sure that I freeze its transforms and delete its history I'm going to repeat this process creating another curve this time I'm going to vertex snap it to the top of the back and once again I'll scale it and I'll freeze this transforms and delete its history and this is going to be my upper back control so if I parent my upper back cluster to the upper back control by middle Mouse dragging and releasing underneath the upper back control and do the same thing with the lower back cluster dragging it beneath the lower back control I now have two curves which I can use to move my clusters you can see that this first joint is sort of getting left behind and we're going to address that in just a minute first list will create one more control right now we can have isolated behavior of the back but we can't really move the upper torso as a full unit so I'm going to create an additional curve this one is also going to be vertex snapped to the first joint in the chain our root joint scale this joint to be a little bit bigger because it's going to influence a larger area on the character I'll freeze its transforms and delete history and I'm going to name this body control and then I'm going to select my lower back and upper back controls and parent them beneath the body control by shift selecting the body control and hitting P I'm going to make sure that shape display is turned off just because it's a little bit easier to see what's going on in our hierarchies and if we expand the body control we'll see that it is the parent of the lower back control and the upper back control and I can use this body control to move the entire upper portion of the character's body alright so in order to move this route joint we've got to associate that in some way with these controls currently the rest of the back is being controlled by clusters but this joint has been left behind the reason we left this joint behind is because having everything controlled by an AI K spline in clusters limits our ability to orient the back joint so this one we're going to connect to the lower back control just using a parent constraint so we'll select the lower back control shift select the root joint and choose constrain parent and we're going to make sure that the maintain offset option is turned on and click apply so now when we move the lower back it pulls the entire skeleton along and the body control pulls the lower back control along which will bring the entire back along for the ride as well so now we'll add an additional control that's going to allow us to move the entire character not just the upper body so I'll create another circle I'm going to scale this one to be the largest of all of my controls and I'll call this the super mover control this super mover our master control is common and it's typically placed at the base of the character's feet and it allows us to move the character around as a unit and in this case we're also going to set it up to be able to scale the character so we'll modify freeze transformations and delete history again and then we're just going to move these elements into the logical hierarchy so I've got a body control that needs to move whenever I move the super mover and beneath the body control I'm already moving the lower and upper back controls and then I've already created some foot controls for this character so those will also need to travel with the super mover control this ika spline back curve should not be parented in with the hierarchy this is already being controlled by clusters and this back ika handle is also not something the animator is going to interact with so I'm going to select both the back ika and the Ikey back curve and group them together by hitting control G and I'll just name this rig group so now I can grab the super mover and it moves the back and the foot controls around but the legs aren't travel correctly and that's because the legs need to be parented to the root so I'm going to select the left and right hip and then shift select the root and hit P on the keyboard or you could middle Mouse drag in the outliner and now the entire character will move together one thing that the character can't do yet though is scale you can see that if I select the super mover and scale it down the controls are scaling but the skeleton only scales at the root joint and the reason for this is that the default behavior of a skeleton is to allow for isolated scaling and this gives the animator the ability to do an isolated sort of squash and stretch on different parts of the character but we want to be able to move this as a traditional kind of hierarchy so we're going to select our root which is the top joint of our skeleton and we're going to group it to itself hitting ctrl G on the keyboard this will be our skeleton group so you can see that by scaling this group node all the joints are scaling so I want to connect the scale of the joints to the scale of the super mover and I'm going to do that using another constraint a scale constraint so we'll select the super-murderer control then I'll also select the skeleton group by hitting ctrl and left clicking here in the outliner and then I'll choose constrain scale you can see that the skeleton group now has an incoming connection and when I scale the super mover the joints scale correctly as do the controls a couple extra elements that I'd like to add to the back rig one is you can see that when I rotate this upper back control it's not really twisting the back correctly it shapes it correctly from a front and side view but the joints themselves aren't twisting so I'm going to do a really simple setup to address this there's more complex setups that we can get into but for this exercise I'm going to select the back control I'm going to feed its Y rotation values into a twist attribute which is associated with the back I K you can find that twist attribute right here I parented the back I K to a rig group and by middle Mouse dragging the twist attribute you can see that that actually rotate those joints along the x-axis so we'll connect those using the connection editor we'll go to window general editors connection editor and on the right side we're going to make sure our back ika is loaded and on the left side we're going to select the upper back control to make the connection editor a bit more readable we'll turn the shown on cable option off and then we'll find the rotate attribute and expand it to see the why rotate attribute will connect that wire rotate attribute to the twist attribute of the back I K so now we have proper twisting when we rotate the back control and Y so this set up is nice if you want to have isolated upper or lower back control it's great for achieving a good C shaped curve in the character but certain behaviors like just bending forward and back can be difficult with an AI K spline setup so I'm going to add one more control that will allow us to rotate the upper back from more of the midpoint in the character's spine so I'm going to create another control again just the circle curve is fine and I'm going to move this control to the lower portion of the back and I'm going to call this back bend control and I'll scale it non proportionately just so that I can see it as a different type of control and again I'm going to freeze the transforms and delete its history and I'm going to insert this control into the hierarchy just beneath the body control so I'll select the back bend control middle Mouse drag and then I'll take the upper back control and parent it beneath the back bend control so this allows me to manipulate that upper back control either from here at the middle of the character's back or if I want to adjust the top of the spine independently I can select the upper back control just as before and with that step out of the way our basic ika spline back setup is done so I hope you found this tutorial helpful and if you're interested in seeing more of my videos please visit my site on lynda.com thanks very much for watching

Channel: Jason Baskin

Views: 147,046

Keywords: IK, back, rigging, setup, tutorial, Jason Baskin, Blake, Blik, Bloke, Maya, animation, Mike and Tina, Lynda.com, IK spline, character

Id: Pj6TrmxhPew

Length: 13min 19sec (799 seconds)

Published: Tue Jul 22 2014