Shape Animation Setup n' Stuff
by Stefan Andersson

I felt it was time to update my shape animation tutorial. There has been some changes in since I wrote the last one, so this is also a update and a "new" tutorial. I've taken this shape thing a bit further and it might be confusing for some people. I suggest that you read all of the tutorials provided from Softimage before attacking this. It's also aimed to people who are about to go beyond the pure basics of using Softimage|XSI.

For this example I'm simply using some spheres that I have deformed. If you do the same you'll get the basics of this tutorial fairly quickly. And also you don't get stuck with fine tuning your mesh model.

Step 1.
Abuse some spheres! And then press "freeze" (which means they are so frozen that they can't mess up your life).

Step 2.
Select the "original" sphere or your neutral shape. In the animate panel chose Deform->shape->Select Shape Key

Pick the other three spheres (or what ever you used). Right click when you have select them and close the popup window that appears. You should now have a sphere with green dots on it. That means you have a cluster(s) on your model.

You can now hide the other objects you used. Don't delete them, if there is a shape you are not happy with you can always unhide it and change the shape afterwards.

Step 3.
Open up the Animation Mixer. Press Shift-S three times to get a few shape animation tracks. Add your beautiful shapes that you made. Right click and chose Load Source -> [name of your first shape].

Do the same for the other shapes (did I need to say that?). Scale them out by grabbing the right end of the shape track. Here comes a step that you can skip if you want, but I find it useful to always make compounds of my shapes. If you have shapes it's much easier to keep track of them and also to go in and change some thing.
Now select them all (click on all of them while holding down shift). Go to Clip-> Create Compound

Now you have only one track, double click on the shape track to access the shapes.

Step 4.
Before we do some thing else we should change how the mixer interprets the curves. If you don't do this XSI will set the shapes to either ON or OFF... nothing in between. And I'm just making a qualified guess that this is not how you want it. So go to MIX->Shape Mixer properties

Uncheck the "normalize" box.

Now we can go back and set up the shapes for animation.

Step 5.
As geeks we looove slider sets... right? no? they are useful though, so let's make one.
Create a null. This null will have our slider set for the shape animation. Personally I like
to set the sliders onto null objects or text objects so
that I can easily select them. Ex:
Graham a character we animated here at filmtecknarna
has a text object parented to his head bone. This way
I can always easily grab his facial animation tools when
ever I need them. Ok I got side tracked here, more tip
will follow after the end of this tutorial.

Slider set... go to Parameter->New Custom Parameter Set. Name it "MyShapes" (really good name wasn't it? hehe)

If you now look in the explorer view and expand the null object you'll notice it has a orange square called MyShapes. This is your slider set.

At this point there are no shape sliders yet so we'll create that now.
Go to Parameter->New Custom Parameter and name it the same name as your first shape.

Lets take a look at the window that appeared.

Leave the default value as it is. But check the UI Range box, then press OK (if you named it). Do the same thing for the next shapes you have. Now you have a slider set. Double click on your orange box under the null and you should have something that looks like this.

Step 6.
Open up the Animation Mixer (double click on the compound track if you don't see the shape tracks). We are now going to use the "link with" command to control our shapes.First drag all sliders in the mixer to 0. On the first shape track right click on the green keyframe button Select "link with".

In the explorer popup you expand the null hierarchy and then select you slider sets first slider, in my case Null->MyShapes->Sphere1. Now you right click again on the keyframe button, but this time you chose "Set Relative Values". Then select your slider set and drag that first slider to 1, then in the mixer drag the first shape slider also to 1 and select "Set Relative Values".
"what did you do?". The relative value you just set was that when you 'animation' slider is at 0 your shape track slider should also be at 0. When the 'animation' slider is at 1 your shape track slider is also at 1.
The great thing about this is that you can exaggerate the shape. Let's say that 1 isn't enough. What you do is that you drag the animation slider to 1 and the slider in the animation mixer you type in a value of 2 (or 3) and then select "Set Relative Values". Test and see what happens after you finished the tutorial.

Now that you fixed the first slider do the same thing for the other two tracks. Pull a few sliders in your slider set and see what happens.


Shape animation tips

As I discussed earlier with null objects and text objects it can also be a good idea to add a camera to the face of the character. As default the camera has a  direction constraint to it's interest. So just remove that constraint and delete the interest.

Then rotate place the camera so that it's looking directly into the face.

Then parent the camera root to the head bone. Now when the character moves you'll always have a camera facing the head and you can conduct you facial animation without fixing a position for a good view.

Despite the pose the camera is always turned to the face.

I hope you had fun and learned something. That's all for now....

Stefan Andersson
Character Animator
FilmTecknarna Animation
Stockholm, Sweden