Posts Tagged Maya

Tell me if you’ve seen this one before…

Oh joy, it’s time to rig faces in Maya.

It’s not something I look forward to, and that probably has something to do with the fact that the first time I went through these motions, I took a very literal path from point A to point B, in which I used wire tools, and cluster deformers to achieve facial movement.

But as with most subjects on this blog, I’m not satisfied with that method, as it’s tedious and time consuming, so this time I’m going to use Blend shapes, which can be equally torturous but for which I’m introducing an intermediary step linking wire deformers and Blend shapes using lattice deformers and cluster deformers to get there.

Here’s my assumed start position:

 

We’re going to start with the mouth and create a wire deformer for it, so I select the appropriate poly-edges around the mouth, and use the Modify>Convert>Polygon Edges to Curve to create the controlling wire.

Like this...

 

Which we proceed to smooth (Edit Curves>Smooth Curve) and make a duplicate of, that we move off to the side.

 

Go ahead and create a new Wire Deformer from the Create Deformers menu using the the original curve and the object with the face you intend to animate.  Now I know I said that we’re using other deformers as an intermediate to get to the Blend Shape deformers, but we’re going to actually create the Blend shape node now, using the two existing curves as the basis.

 

 

Hey, they're linked, just like they should be, and scaled by the Blend shape node, which is what we're looking for in terms of general behavior.

 

This is good, but the curve has so many control points that adjusting them for each shape will be almost as much of a pain as if we were adjusting verts by hand on the model.  We could weed them out, but the fit would be sacrificed, not to mention that we’d have to delete the same CV’s on both curves in the same order to keep the Blend shape working as intended.
Rather than get bogged down in all that, create a lattice deformer around the top and bottom CV’s respectively.  For demonstration purposes, I’ve just done the top set here for clarity.


The advantage of lattice deformers is that they take high density curves and polys and smooth the deformation over a larger area.  We can control those now by manipulating clusters we can attach to the lattice points as seen in the second of two images above.

 

Here's a sample manipulating the Cluster as a control for deformation.

 

Let’s say this is the expression we want for our next blend shape.  Duplicate the secondary curve in its’ deformed shape and add that as your next blend shape target.  A new target with slider shows up in the Blend Shape window.  Sliding it produces a duplicate of the exact same deformation that you got a moment ago manipulating the cluster.  Another benefit of the cluster deformer, is the ability to reset its’ position back to ‘zero’, over and over again, repeatedly creating new Blend Shape targets, and so on and so forth.

 

Lastly,  it should be noted that Blend Shape deformer nodes, as long as they are defined as “Local” when created, are free to be attached directly under the character or skeleton’s node without having to account for double transformations, a tedious step involved in most other types of  animation control rigs.  Just remember to parent both the wire and the baseWire shapes to the appropriate part of the anatomy and/or rig, and the blend shape should still work as intended.

 

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Building on knowledge

I’m going to build on the last two weeks’ worth of discoveries with a bit of a slide show indicating some of the variations of this new-found technique as I went through and finished the model’s head.  Combining these with what we’ve gone through already, it’s starting to form a picture of a comprehensive skillset that can efficiently model entire figures.  If I can compare it to anything, I’d compare it to custom plate fabrication, where you break down your character into a set of plates or shapes, and those plates have to be fabricated to fit the number of polys along each edge.  So any way you can arrive at what the parameters of each plate are, then you can apply the techniques already discussed.
For example, as some of the illustrations below will demonstrate, even if you can landmark key points of a surface in three-dimensional space say… using Locators for example… you can string curves through them forming the boundaries you need to proceed.

You can see the green cross-hairs I strung the EP curve tool through to achieve the cheekbone area of the face.

If a shape is a little too awkward to do in one pass, you can always break it down further, as described in the previous entry.

Bottom of area...

The bottom part of the same area.

And bridging the two together.

But what if, for example, the rest of the body you’re going to attach this head to only has 16 polys around the neck, while your head is being  modeled at a higher poly count?  This isn’t all that unexpected a situation, as the face often is modeled at higher resolution for the sake of accommodating the smaller features of the face as well as providing smoother animation for the subtleties of facial movements.  The rest of the body isn’t as nuanced as this, except perhaps for the extremities of the hands and feet.  In any case, the gap must be bridged, unless the parts behind clothing aren’t going to be modeled at all (binding multiple objects representing the emergent and visible parts of the model only).  I ran into that situation here.  I wanted to limit the back left quarter of the neck to a width of four polys.  But this is what I had to work with:

Yeah...

If you look carefully, you can see already my thought process.  I intend to take the last four polys and spread them out wider, but there isn’t a place for those remaining five polys to go, right?

OR

IS

THERE?

Now the extra polys have been routed around the base of the neck rather than down the neck into the rest of the body.  I did partition out the neck area to receive them too, but that’s a function of the principle above about sub-dividing areas.

I’ve modeled a couple more heads and a hand in the span of time betwween last week’s entry and today’s using these procedures and I have yet to run into a situation that using it, in conjunction with a little creative thinking, hasn’t been able to resolve.  The hand I did already had the rest of the model waiting for it, but when I imported it in, I was confident that it would blend seamlessly with the rest, and it did.  That’s not something I can say for all the character modeling work I’ve done thus far, but alas, I didn’t know then what I know now.

But what if you want a surface with a continuous, smooth, single edge loop of polys running around it, rather than a shape bounded by four separate edge loop flows?

Go from this...

To this...

By merging to center these three vertices in each 'corner'.

That’s it for this week.  If there’s more to be mined from this method that I can dig up, you’ll see it shared here.  Until then, the subject may wander to other venues again…

Fin.

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