This example will show
you how to create a flexible skin for a virtual balloon.
Create the balloon
To model the balloon
you will create a Icosahedron. This will result in more realistic
movement than a polygon sphere.
To model the balloon
- In the Polygons menu
set select
Create > Polygon Primitives > Platonic Solids > .
The Polygon
Platonic Solid Options window appears.
- Set Platonic Type to Icosahedron and
click Create.
- Select
Mesh > Smooth.
- In the Attribute Editor,
select the polySmoothface1 tab.
- In the Linear Poly Smooth History section
adjust the attributes as follows:
- Method: Linear
- Division Levels:
1
- Divisions per Face:
3
- Push Strength:
0.8
- Roundness:
2
Resize and reshape the
balloon
In this example the balloon
model for the balloon will remain spherical. You can optionally
reshape the model into a more balloon-like shape.
- Select the balloon and select the Move
Tool.
- Move the balloon above the ground plane
(in the positive Y direction).
- Select Smooth Shade All mode
(hotkey: 5).
- -click
the balloon and select Face from
the marking menu that appears.
The balloon now appears
in face selection mode.
- On one side of the balloon, select 6
adjacent faces that form a hexagon.
- Press .
The selected faces are
deleted.
Make the balloon model
nCloth
- In the nDynamics menu
set select the balloon and then select
nMesh > Create nCloth.
Maya converts the polygon
balloon into an nCloth object.
Make the balloon model
act like a balloon
Now that you have the
basic shape for your inflated balloon, you need to configure the
balloon’s attributes so it acts like a balloon and its initial state so
it starts deflated.
To adjust the balloon's attributes
- Select the balloon.
- In the Attribute Editor,
select the nClothShape1 tab.
- In the Collisions section
set Thickness to 0.02.
- In the Dynamic Properties section
set Stretch Resistance to 80.
- In the Pressure section
set Pressure to 0 and Seal
Holes to On.
- In the Quality Settings section
set Evaluation Order to Parallel.
- Select the nucleus1 tab.
- In the Ground Plane section
turn on Use Plane.
- Set the End Time of the playback range
to 450.
- Playback the simulation.
The deflated balloon
falls to the floor.
To set the balloon's initial state
- Go to the beginning of the playback range.
- Select the balloon and select
nSolver > Initial State > Relax
Initial State > .
The Relax
Initial State Options window appears.
- Select Edit > Reset Settings.
- Set Steps to
200 and click Relax Initial State.
Maya will automatically
playback the scene to frame 200 and save the balloon simulation
to disk.
- Select
nMesh > Rest Shape> Set
Rest to Start Shape.
The balloon begins its
simulation in its deflated form.
Inflate and deflate the
balloon
Now that the balloon
begins deflated you can animate the balloon inflating and then deflating.
To inflate the balloon
- Go to the beginning of the playback range.
- Select the nCloth balloon.
- Open the Channel Box and
under Inputs, select nClothShape1.
- Select Pressure and
then -click Seal
Holes to include it in the selection. -click
either name and select Key Selected from
the context-sensitive menu that appears.
The fields will change
color to confirm you set the keys correctly.
- Go to frame 200 of the simulation.
- Set Pressure to
10.
- Select Pressure.
- -click
the name and select Key Selected from the context-sensitive
menu that appears.
- Playback the animation.
The balloon inflates
very quickly initially, and then slows down until frame 200.
To deflate the balloon
- Go to frame 300 of the animation.
- In the Channel Box,
select Pressure and -click Seal
Holes to include it in the selection. -click
either name and select Key Selected from
the context-sensitive menu that appears.
The fields will change
color to confirm you have set the keys correctly.
- Go to frame 301 of the animation.
- Set Seal Holes to off.
- -click
the name Seal Holes and select Key
Selected from the context-sensitive menu that appears.
- Go to frame 450 of the animation.
- Set Pressure to 0.
- -click
the name Pressure and select Key
Selected from the context-sensitive menu that appears.
- Playback the simulation.
At frame 300 the balloon
flies away due to the release of air from the hole in the geometry.