Wrecking Ball

Owned by thomas (Unlicensed)
Last updated: 18 Jul, 2015
3 min read

This setup shows you how to destroy a fractured wall with a wrecking ball. A sphere falls down and crashes into the wall, and destroys it. A → MultiJoint constraints the sphere to the mounting and acts like a rope.




The scene setup with the wrecking ball, a prefractured wall, and MultiJoints.


Here is the nodes list:

  • 2 “Sphere” objects (wrecking ball, steering geometry)
  • 3 “Cube” objects (wall, mounting, ground)
  • 1 “Null” object (locator)
  • 1 “Gravity” daemon
  • 2 “MultiJoint” nodes

 

All scene elements can be added from RealFlow's “Edit” menu:

  • Add > Objects | Daemons

  • RealFlow nodes can be moved, scaled, and rotated with the W, R, and E keys.

  • Imported objects from SD files have to be unlocked before they can be transformed with Selected object > Node Params > Node > SD ↔ Curve

  • Viewport perspective is changed with the 1, 2, 3, and 4 keys.

  • Shading modes are toggled with the 7, 8, 9, and 0 keys.

The Setup

  • Add a cube object and rescale/position it to your needs. This node (“Cube01”) will serve as the wall.

  • Create another cube (“Cube02”, the mounting) and place it somewhere above the wall.

  • The third cube (“Cube03”) is the ground node

  • A sphere is used as the wrecking ball (“Sphere01”) and positioned next to the mounting.

  • A null (“Null01”) )is placed directly below the mounting.

  • “Gravity” introduces a force.

All polygon objects are passive rigid bodies, except the sphere (active rigid body):

  • Selected node > Node Params > Node > Dynamics

Now, add a MultiJoint and open its “Creation” panel under “Node Params”:

 

 

  • Objects A > Sphere01

  • Objects B > Cube022

  • Creation mode > At Locators Positions

  • @ Locators > Null01

  • Create/Recreate

Determining the Zone of Impact

  • Simulate the scene. If the sphere does not hit the wall, reposition the wrecking ball rig and/or change the distance between the sphere and the mounting.

  • When everything is adjusted correctly, go back to the frame where the sphere hits the wall and place another sphere (“Sphere02”) inside the wall node. Make it slightly bigger than the wrecking ball.

Create the Fractured Wall

 

  • Select the wall node (“Cube02”).

  • Open the “Voronoi by Steering Geometry” tool from the "Tools" shelf.

  • Enter the values as shown below and click on “OK”.

  • Delete the “Sphere02” and “Cube02” objects – they are not needed any longer.

  • Change the new object's “Dynamics” mode to “Active rigid body”.

Reconnect the Wall's Fragments

Right now, the fragments will start to break apart when you start the “Simulation”. Therefore, you have to reconnect them:

 

 

  • Add another MultiJoint node (“MultiJoint02”).
  • Open the MultiJoint's “Creation” panel under “Node Params”.
  • Objects A > Cube03, Cube01_fractured01
  • Objects B > Cube03, Cube01_fractured01
  • Create/Recreate
  • Forces > Force max mode > Constant limit
  • @ Max force > 150000
  • Collisions > Enable if break > Yes
  • Break > Break if distance exceeded > Yes

Simulate

Click on “Simulate” to see the results. Play with different “@ Max force” settings of the “MultiJoint02” node to get different degrees of destruction.