Claudia Herbst
Associate Professor
Pratt Institute
Department of Digital Arts




Growing a Softbody Using an Emitter

This "tutorial" is in progress - suggestions welcome: cherbst@pratt.edu

1) Make sure that your Playback Speed is set to Real-time 24 FPS. Set your frame range to 400.

2) Create an emitter and, in the Outliner, delete its particles

3) Create a NURBS sphere, scale it by 5 units in X, Y, and Z. Increase the number of sections
and spans to 20 each. Freeze transform the sphere and delete its history

4) With the sphere selected, go to Soft/Rigid Bodies, create a Softbody. In the options box:

- set Create Options to Duplicate, Make Copy Soft
- check the Make Non-Soft a Goal option
- set the Weight to .750


5) Go to Window, Relationship Editors, Dynamic Relationships.

6) In the left panel of the Dynamic Relationships Editor, select the copyOfnurbsSphere1 object.
To the right, under Selection Modes, check Emitters. The emitter1 should appear; click it to establish a link between the emitter and the soft object.

7) Open the emitter in the Attribute Editor and set the following...

Under Basic Emitter Attributes:
- set the Emitter Type to Omni (should be default)
- set the Rate to zero

- click the copyOfnurbsSphere1ParticleShape tab (top of window)
- change the Lifespan Mode to Constant (leave the value at 1)


Under Softbody Attributes:
- deselect Enforce Count From History


8) Make sure you're at frame 1 and hit play. The softbody object should disappear after frame 24
(the original sphere will still be visible...).

9) Go to Solvers (main menu), Initial State, Set for All Dynamic (normally we'd be more selective
but since there's only one Dynamics object ...)

10) Now select the original sphere, which is still visible, and hide it.

11) Next open the Emitter in the Attribute Editor again and change the Rate to 50.

12) Select the copyOfnurbsSphere1ParticleShape and, in the Channel Box, set the Goal Weight to .75,
the Goal Smoothness to 1, and set the Lifespan to 15.

13) Make sure Goal Active is on. Try playing it back - the sphere should grow...

14) Play with the Goal Smoothness attribute - try a higher value (I like the look of a value of 3...)
Also, try changing the Goal Weight to a .5 ... experiment with the emitter rate.