Paint Effects
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Soft Bodies

Soft Body Dynamics

Can create geometry that is flexible. It can bend, ripple and bulge.

Can make softbodies from geometry or lattices.

Maya makes a particle for each CV or vertice.

Fields such as gravity and turbulance effect the particle and then the geometry is effected.
Collisions affect the particles and then the particle moves the geometry.

You can make have the soft body move towards or follow a goal.
You can paint weights to have different parts of the geometry affected differently. This can be used to set goal weights of the particles on the soft body object.

You can set springs on a soft body object. The springs connect the particles inside the object and keep it from jiggling too much. You can also use springs to connect softbody particles to other particles or geometry.

You can also emit particles from a soft body surface or its particles.

Creating Soft Bodies:
Can use polygons, NURBs surfaces and curves, lattices

1. Select the geometry that you want to be a soft body
2. Dynamics menu set - Soft/Rigid Bodies - Create Soft Body - Options


OPTIONS:

Make Soft

Select this if the object has not been animated and you want to effect it with fields OR has been animated with keysor deformers. If the object is animated using keys or paths, the soft body particles will not be effected by the momentum of the non-dynamic motion.

Exercise:

1. Create a sphere and set a Key on Position then move the sphere and set another key.
2. Select the sphere and change it to a SOFT BODY
3. Play the animation and stop
4. With the sphere selected, add a TURBULANCE field and adjust the magnitude.
5. Play the animation

Duplicate, Make Copy Soft

This will make a copy of the geometry so that one copy can be used as a goal (Make Non-Soft a Goal). You can change the goal weight so that when the original follows the copy as a goal, it can jiggle or be more stiff. The original geometry is the goal and the new copy is the soft body. If you do not turn the non-softbody into a goal, you can use this to make lots of copies of soft body objects.

Exercise:

1. Create a sphere and make it a SOFT BODY - Duplicate, Make Copy Soft with Make non-soft a goal clicked ON
2. Open the Outliner to find the original sphere and then animate it - use rotation and position
3. Play the animation
4. Open the Outliner and select the particles and Open Goal Weights and Objects
5. Set the goal weight by moving the slider next to (nurbs or poly)SphereShape1
6. Adjust Goal Smoothness to control the timing of the goal attraction

Exercise 2:

1. Create another object and make it a Soft Body - Duplicate, Make Copy Soft with Make non-soft a goal clicked ON
2. click Hide Non-Soft Object and set the Weight in the Options.
3. open the outliner and see the hidden goal
4. You can animate this object to be a goal but it will not render

***Don't forget you can hide and show objects - Display > Show > Show Selection OR Display > Hide > Hide Selection

Duplicate, Make Original Soft

Used primarily with IK splines


Adding Fields to Soft Bodies

Add the field to the Soft Body object NOT the non-Soft Body
Make sure you use the Outliner to select the non-soft body object

***If you select the WRONG object (the non-softbody) and add a field, it will become a rigid body body - not good! Undo


Getting Control of the Soft Body Shapes:

To control the behavior of the soft body shape you can:

Edit Goal Attributes
Paint Soft Body Weights

Add Springs (will discuss later)


Making an object a goal

Select the soft body particles and Shift-Click the goal object then Particles - Goal


Edit Goal Attributes

Goals can be any object except a curve on a surface. You can have more than one goal for a soft body object.

Weights
***how much attraction to the goal
Goal Weight of 0 = bend and deform freely
Goal Weight of 1 = follows the goal shape and position exactly

Conserve
Set the trailing(not the goal) object's Conserve to less than 1 to avoid oscillation.

Goals OFF and ON
Select the particles and Attribute Editor - Goal Weights and Objects
Turn Goal Active on or off

Creating Per Particle Goal Weights
In the Attribute Editor for the soft body particles, select Goal Weights and Objects
Click the Create Goal Weight 0 PP (this disables the overall goal weight)
Look in the Per Particle (Array) Attributes and find Goal Weight 0 PP - 0 is the first goal, if you had more than one goal it would have 1, 2 etc.

Goal PP is multiplied by the value you give the Goal Weight 0 PP.

To turn off per-particle goal weight attributes

In the particle system node in the Attribute Editor, go to the Goals and Weights section and click the Delete goalWeightNPP button

Exercise: Set the PP Goal Weights

1. Create an two objects (one can be a curve).

2. Make one a soft body and one a goal (use any method you have learned).

3. Animate the goal.

4. In the Select by Components, select the individual components you want to add individual weights to.

5. Select the partcilces of the soft body and turn on Create goalWeightNPP

6. Go to Per Particle (Array) Attributes and right-click next to the goalWeightNPP attribute and select Component Editor

7. Select Window > General Editors > Component Editor.
(If the goalWeight columns do not appear, in the Component Editor menu select Options > Hide Zero Columns)

8.Play the animation and stop in the middle.

9. Edit the goalWeight values in the Component Editor.


Paint Soft Body Weights

Exercise: Using the Help Menu, select Dynamics - Soft and Rigid Bodies - Soft Bodies
On this page about half way down, click Paint Soft Body Weights Tool

Do as many of the following exercises as time allows

1. Create a piece of cloth that flaps in the wind
2. Create a cube of jello that bounces when dropped
3. Create a rope that is flapping in the current of the river (the rope is underwater and you do not need to make water)