Friday Flashback #152


Kaboom! “In SOFTIMAGE|3D, the Effects > Kaboom custom effect in the Motion module allows you to explode complete hierarchies using dynamics and collision detection. Now you too can create your own earth-shattering kabooms!”

1997 screenshot
kaboom

Exploding Hierarchies with Kaboom

The Effects > Kaboom custom effect in the Motion module allows you to explode complete hierarchies using dynamics and collision detection. Now you too can create your own earth-shattering kabooms!

Features include:

  • Speed.
  • Complete interactivity. Move the source of the blast around and the pieces rearrange themselves.
  • Collision detection: bouncing and sliding.
  • Hierarchies: explode a whole hierarchy instead of individual objects.
  • Non-polygon mesh objects are treated as solid objects.

Using the Kaboom Effect

The Kaboom effect explodes the currently selected hierarchy. Dynamic calculations are done on the object, including gravity, wind, and collision detection with a ground plane. Objects can collide with the ground plane (from either side), bounce, and slide (continuous contact). Polygon mesh objects can be exploded into their constituent polygons.

Here’s an example of how to use the Kaboom effect:

  1. Get a primitive cube.
  2. Choose the Effect > Subdivision command in the Model module to subdivide the cube into polygons. Use the default values: 4, 4, 4.
  3. Choose the Polygon > BreakUp command in the Model module to “separate” the cube into polygons.
  4. Translate the cube upward so that it is completely above Y=0.
  5. Get a primitive grid.
  6. Choose the Effects > Kaboom command in the Motion module. The Kaboom dialogue box appears:
  7. Accept the default values and click Ok.
  8. You are prompted to select the ground object (click the grid).
  9. You are prompted to select the hierarchy to explode (click the cube).
  10. Play back the animation. The cube explodes and collides with the ground.

For a full description of parameters, see this command’s description in the Reference Guide.

Tips for Using the Kaboom Effect

  • If you are exploding polygon meshes, make sure to use the Polygon > BreakUp command in the Model module on them first (or PolygonDetach); otherwise the polygons stay connected.
  • If the Explode Meshes option is selected, polygon meshes are exploded into individual polygons. If Explode Meshes is deselected, polygon meshes are treated as solid objects. All other object types (NURBS, patches, nulls, etc.) are always treated as solid objects.
  • Don’t worry about deselecting Collision Detection for greater speed: it doesn’t slow things down much (if at all).
  • Deselect Tumble Rate unless it is required: it slows things down by at least half.
  • Polygon grouping is logical, not topological. This means that polygons are grouped according to their order in the model, not according to the geometry of the model.
  • The Collision Detection for the ground is based on the Y height of the object selected for the “ground” object: the plane at this height is used as the ground plane. The collision detection is not based on actual geometry.
  • The ground plane is double-sided-you can bounce an object off it from above or below.

Things to Try

  • Use a strong Pull value with a slow speed: it tears objects apart.
  • Move the Kaboom effect icon around and watch the blast rearrange interactively.
  • Use a negative value for the Falloff power: the blast strength increases with distance from the icon.
  • Use no Blast Strength (value of 0) and a slow Speed to “collapse” your model.
  • Create a strong blast with a 0 distance Falloff, high Bounce, some Tumble, and very little Slide, and place it above an object that is close to the floor. You’ll get a nice “splashing” effect.

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