Attaching an animatable Head to an animatable Body


So this is a tutorial on how to attach an animatable head to an animatable body in Max 4 ready to use morph targets and physique. It's aimed at intermediate users who want to get simple animation rigs together for their characters using just morph targets and character studio. This tutorial was created in Max 4.2, but things are pretty much the same for any version of Max from Max 3.0 and up.

First off, create your entire character. There's a very simple one here (right). Nothing special, but it will do for the purposes of this tutorial. Notice the entire body and head are modelled together (lower left), in one simple model.

What we want to do here is create a character with various facial expressions, be they used for talking, just plain emoting, whatever. Having modelled it, texture away to your heart's delight. I think most people tend to texture the face and/or head
independently of the body, feel free to do that, in the end, we just one want one clean mesh though, so I've just collapsed this to an editable mesh. As I said, this is a very simple demonstration model so I haven't gone to too much trouble texturing her - so shoot me.

The stack in Max is read from the bottom up, and this is crucial to the whole setup. What we will be attempting to do is start with a head, apply morph targets to it, add the body, and then add physique. As Max reads the stack from the bottom up (right), it reads this as: here's a head, apply whatever morph targets are required, now add a body, and now move that body according to physique. Finally, smooth the entire thing.

The reasons for this setup are as follows:

First off, there's no sense you having an entire body and morphing every single vertex of that body for small changes that appear in the head alone. If it's only the head that's animated, well then that's the only thing worth morphing. You'll be relying on character studio to do the animating of the body, and you want the facial expressions separate.

Second, adding the Edit Mesh afterwards means that we can now add a body to our morphed head, welding the two together, but still allowing us at any time go back to the morpher in the stack to animate at will, so we need this here if we are to have a body welded to the head. I use this because it means the entire mesh can be one object, this means you don't get problems with meshes pushing out over each other (i.e the neck of the head coming through the body when the head looks up or down), you have no visible seams or holes in the mesh, and you can better define how things deform in one single contiguous mesh anyway.

Third, Physique is applied after the Edit Mesh so it applies to the entire body, morphed head and static body included.

Finally, if we put Meshsmooth at the top of the stack, Physique won't have so many vertices to calculate when it's deforming your mesh (using Biped).

Once that's done and you're happy with your character's base pose, let's go ahead and decapitate it. Choose the area on the model that you feel needs to be part of your morph setup, usually your head.

I tend to cut them off at the neck as it seems a reasonable area to do it from (I still haven't come across the need to animate someone's chest as a morph target - if it ever happens I'll let you know). Just select the polys of the head to the neck (left), and hit detach (right). Name this base head. Hide
the body.

Now duplicate your head, just copy the existing head as a copy (make sure it's not an instance) (left), and start creating your morph targets. Create as many as you like here, in fact, the more the better. Just push and pull the vertices to
the facial expressions you want:

When editing these new heads to different expressions make sure not to add or delete any faces or vertices as this will stop it from being a valid target. I sometimes add a meshsmooth on these temporaily to see what it will look like with the final meshsmooth on top, but remember to remove it afterwards when you're happy, or as I said, the vertex count will differ from your base head and it won't be recognised as a valid morph target later on. Once you've got a few heads together, it's time to get cracking on the final setup. Make sure your heads are named in a way that you recognise (i.e the head with a smile should be called "smile", etc - it just makes things easier later on if you do this now). Select your base head, apply the Morpher modifier to it (left) and add your morph targets (right). If they don't come up as valid targets, (below) well, that's because you've either added or deleted vertices, or forgotten to take off the meshsmooth on your morphed heads. For shame, I warned you about that. Now you've gotta do that head's expression again.

Once done, feel free to check that your morpher modifier is working correctly. Play with it and make sure you're happy, it's easy to edit any of your heads again, and now is a good time to do it. Try mixing them up a little, just to see how the different expressions mix together. If you don't like one, edit it, and just hit Reload All Targets in the morpher modifier(left) or just leave Automatically reload targets checked on.

Once done and you're totally happy with it, move on to the next part - attaching your body.

Unhide your body, and it should hopefully still be perfectly aligned with your base head. If for some reason it isn't, align it now. Once done, select your head and apply an Edit mesh modifier (right). Attach the body to the head with Attach (lower left), select the vertices at the neck where the two meshes join (below), weld the vertices together, and wham!, there you go, full body with animatable head attached, with no seams or holes in your mesh. Create and align your Biped, and now apply Physique to your mesh, and bind it to the Biped. Fix up your vertex assignments as normal.

Throw a Meshsmooth on top of all this (if desired/required) and you're done. You can now go back down the stack at any time and animate you morpher parameters.

Of course, if the teeth are separate, it can be a good idea to use Max's wire parameters dialog to rotate the teeth properly in the head according to the percentage of the morph target for "open mouth". But that's another tutorial for another day. Your character should now be ready for animation with biped, and with a full set of facial expressions. Now the hard bit, animate it. Hope this has helped anyone looking to do this. It's by no means the only way to do it, it's just the way I sometimes do it for simple models. Any suggestions/criticisms/outright mistakes, let me know atán

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