November 20, 2014
Workshop 17
Notes
Blend Shapes, Set Driven Keys, and nParticles (Revisted)
PART
I: Blend Shapes
Part
1 of this workshop is developed after the on-line tutorials provided in
the Robinson Text. For a more complete treatment from within UVA, go
directly to the on-line
reader and review pages on the
Bend Deformer beginning at page 321.
- Goto to the
Surfaces module and create a sphere.

- Make a copy of the second
sphere. From the " Edit Menu>Delete
By
Type" option, select and delete the history of second copy of the
original sphere. Make some changes to the shape of the thirds sphere.
- Go to the Animation Module,
select the second sphere, shift-select the third sphere,
shift-select the first sphere , and then to the menu item
"Create Deformers>Blend Shape"
- Choose Window >
Animation Editors > Blend Shape.
Go to the blend shape you want to animate, move the target
slider, adjusting the weight of each blend shape to create
the
transformation desired in the first shape.
Note that the original shape is deformed accordingly.
- Use the "Key"
button to set the added shapes with the
desired weight at specified frames with the animation.

- Place the second and third
shape on separate layer and turn it
off.
- Playback the animation.
PART II: Use of set Driven Keys
- Create a sphere and a cone.
- In the Animation module, go
to the menu sequence Animate
> Set Driven Key > Set
- Select the sphere, and in
the "Set Driven Key" dialog box, go to
Load>Select as Driver.
- Select the Cone, and in the
"Set Driven Key" dialog box, go to
Load>Select as Driven.

- Now, connect parts of Drive
list with parts of the Driven list.
For example, select the "Translate Y" attribute of the sphere with the
"Rotate X" attribute of the cone, and set the "key" for each one.


- Move the sphere up and
rotate the cone around the Z axis, and set
the key again.

- Now, move the sphere up and
down and the cone is adjusted
accordingly.
- Finally, key frame the
sphere at frame 1, frame 12, and frame 14
and three different positions along the Y axis from its first location
in step 5 to its final location in step 6, and playback the animation.
Note that the cone is animated as well.
- Similarly, one can rig a
character using the same technique. Using the same methods, the
illustration below is developed a with horizontal surface plane
rotating around the "X" axis as a driver, and the IK handle on the leg
of a skeleton moving up and down along the "Y" axis as the driven.
Thus, rotating the horizontal plan drives the up and down motion of the
leg.
PART III: nParticles revisited (self-colision and size emphasized).
nParticles are capable of self-colision, and therefore can simulate
liquid bodies.
- Make a polygon object that
looks like a cup or pail, such as by
starting with a polygon cylinder and removing the faces on the top
surface of the cylinder.
- Go to the nDynamics module.
- Go to menu item
nParticles>Create nPartices > Create Emitter
- Move the emitter so that it
is inside the cup and above the cups
bottom surface.
- Select the cup's geometry,
and got to menu item nMesh>Create
Passive Colider
- Select the particles, and go
to the menu item Fields>Gravity
- Select a particle, go the
the attributes editor icon, open the
nParticleShape1 tab, go to the "Collisions" section, and turn on the
check-box for "self-Collide.

- Go the particle size tab,
and adjust the radius.
- Play the animation for 500
frames and see what happens.
- Place a polygon plane below
the cylinder and make it into a
passive collider.
- Finally, key frame the
cylinder spilling over, and see what
happens to the particles.
