1. Computer Animation Ying Zhu Georgia State University
Deformation

2. Deformation techniques
Modifiers
SimpleDeform
Cast
Curve
Lattice
Shape keys
Relative shape keys
Absolute shape keys

3. SimpleDeform Modifier
Apply simple deformations to the target object
Twist
Stretch
Bend
Taper
Change the Factor to adjust the scale of deformation

4. Cast modifier
Cast an object to the shape of Cuboid, Sphere, Cylinder

5. Curve modifier Add a curve to the scene, give it a name
Add a modifier to the target object (e.g. a piece of paper, etc.)
Type in the name of the curve
Now you can manipulate the curve to deform the target object
Subdivide the target object to get more realistic deformations
Good for animating papers, cloth, eye brows, etc.

6. Lattice modifier
Use lattice to deform the space occupied by the lattice and everything in that space.
Press Space bar and add a lattice
Give it a meaningful name
You may want to scale it
Under Editing (F9) panel, Lattice tab
Change the values of U, V, W to adjust the resolution of the lattice
If you wan to deform the object now, surround the target object with the lattice.

7. Lattice modifier Select your target object, add a Lattice modifier
Type in the name of the lattice in the “Ob” field
Select lattice, enter Edit mode
Now manipulate the vertices on the lattice to deform the target object
Changing the overall size of the lattice doesn’t change the size of the object
It’s deformation of lattice that deform the object.

8. Lattice modifier
You may place the lattice away from the target object, and then move the target object to pass through the lattice.
The object will be deformed in the region where the lattice is deformed
In the above process, you may create key frames for the target object so that it’s deformed in the middle of the animation

9. Lattice parenting
Besides lattice modifier, there is another (old fashioned) method to attach a lattice to a target object
Select a target object and then select a lattice
Press ctrl + P, choose “Lattice Deform”

10. Relative shape keys
Relative shape keys are commonly used for animating facial expressions
Shape key is like key frames for deformation
You define a basis shape key for an object and subsequent shape keys
Each subsequent shape key is based off of the basis shape key
Usually not a good idea to delete vertices in shape keys

11. Relative shape keys Relative shape keys provide a lot of flexibility
You can mix different shape keys
You can adjust the influence value for any shape key to create a shape that’s somewhere between the basis shape key and this shape key

12. How to add relative shape keys?
There are several ways to add shape keys. But I found the following method to be the most robust.
Select a target object, enter Edit mode
Under Editing (F9) panel, select “Shapes” tab
It’s next to the “Modifiers”
Press “Add Shape Key” button
The first time you press this button, the basis shape key is created.
By default the “Relative” button is pressed

13. How to add relative shape keys?
Press “Add Shape Key” button to add another shape key
By default it’s named “Key 1”, “Key 2”, etc.
You may want to give them meaningful names (e.g. smile, sad, open, etc.)
Deform the target object in Edit mode
When you are done, press Tab key to leave Edit mode, and then press Tab again to enter Edit mode
The shape key is saved at the moment you leave the Edit mode

14. How to add relative shape keys?
Repeat the above process to add more shape keys
Sometimes you may want to enter Object mode, go back to the basis shape key, and then enter Edit mode to create another shape key based on the basis shape key

15. Shape keys for lattice
The above process works for both meshes and lattices.
This means you can create shape keys for lattice deformations
You can select a lattice, enter Edit mode, add a shape key, deform the lattice (which in turn deforms its associated object), leave Edit mode, then enter Edit mode, add more shape keys, and so on.

16. Shape keys for curve You can add shape keys for curves
Select curve, enter Edit mode, deform the curve
Press I to bring up the Insert Key menu
Select curve
Leave Edit mode and then re-enter edit mode
Repeat the above process to add more shape keys for the curve

17. How to add relative shape keys?
In the Object mode, select the target object, you can review the shape keys by pressing the left and right arrow buttons in the “Shapes” tab (in Editing panel)

18. How to animate with shape keys?
There are several ways to insert shape keys to an animation
Insert shape keys into the Shape IPO curve
Insert shape keys in Action Editor (ShapeKey Editor)

19. Editing shape IPO curve
Select the object that you have defined shape keys for, open IPO Curve Editor window
In “Ipo Type”, select Shape
Blender has separate IPO curves for shape keys
You’ll see all the shape keys in this window
Select any shape key to view and edit its curve
If a curve doesn’t exist, enter Edit mode, press ctrl + LMB to add new point and a new curve

20. Editing shape IPO curve
The vertical axis represent “influence”
Allowed values are between 0.0 to 1.0
Each point on the curve means how much of that shape key will affect (deform) the mesh at any given frame.
If there are multiple shape curves at one frame, it means the final shape of the object is a combination (blend) of several shape keys.

21. Mixing relative shape keys in ShapeKey Editor
Select the object that you have defined relative shape keys for, open Action Editor window
In Editor Mode menu, select ShapeKey Editor
You need to have a Shape IPO curve for each shape key to see shape key slider bars in the action editor
These are the sliders for changing influence of each shape key

22. Mixing relative shape keys in ShapeKey Editor
To add a relative shape key for a particular frame, move the green vertical line to that frame, and then move the slider bar for that shape key.
The moment you touch the slider bar, a marker will be added for that frame
You can delete and move the markers
You can insert relative shape keys along horizontal lines (shape change over time)
You can also insert relative shape key along vertical lines (mixing shapes for one frame)

23. Mixing relative shape keys in ShapeKey Editor
Along the horizontal (time) line, you need to decide when you want a shape key to appear, when you want it to reach full deformation (influence = 1.0), and when the shape goes back the basis shape
For example, you add a “smile” shape key with influence = 0.0 at frame #20
Then add the “smile” shape key with influence = 1.0 at frame #80
Then add the “smile” shape key with influence = 0.0 at from #200

24. Mixing relative shape keys in ShapeKey Editor
This means you will start to see the “smile” at frame #21
Gradually the “smile” will reach its full deformation at frame #80, and then gradually goes back to the basis shape at frame #200
Blender will automatically interpolate between the same shape key inserted at different frames
Relative shape keys are interpolated along horizontal lines

25. Mixing relative shape keys in ShapeKey Editor
Along vertical lines, you can insert multiple shape keys for one frame. Blender will combine (blend) them.
For example, you have both “shape key 1” (influence 0.3) and “shape key 2” (influence 0.7) for frame #20.
This means at frame #20, the shape of target object is a combination of 30% “shape key 1” plus 70% “shape key 2”.
Relative shape keys are blended along vertical lines

26. Adjusting shape IPO curve
After mixing relative shape keys in ShapeKey Editor, you can switch to IPO curve editor to adjust the Shape IPO curve
Adjust how fast or slow a shape key reaches its full deformation or disappears

27. Mixing relative shape keys in ShapeKey Editor
The ability to mix multiple shape keys is very useful
It makes it possible to create complex animation by combining a few simple shape keys
Particularly useful for animating (mixing) facial expressions
For example, mouse open 70% plus left eye open 50%

28. Absolute shape keys
Difference between a absolute shape key and a relative shape key
There is no “influence” value for an Absolute Shape Key
You cannot apply 70% of an Absolute Shape Key
You cannot mix absolute shape keys in the ShapeKey Editor
Otherwise they are similar