The Physics – Particles object is a particle generator. It creates myriads of particles in the physical world, with various speed and directions. It is very flexible and can be used to your heart’s desire.

The Properties

• Emission
  This property allows you to define where the particles will be created.
  • From a point
    The particles will be created at the exact position of the particles object, from a single point.
  • From a zone
    The object can be resized : the particles will be created at random in the zone defined by the object.
• Create particles at start of frame
  The object will emit particles automatically when the frame starts if this property is checked. If not checked, you will have to use the “Create particles” action.
• Creation speed
  If the previous property is checked, this property contains the speed at which the particles are created.
• Number
  This property contains the number of particles to create at each loop. Warning, high numbers can flood the screen very rapidely (and slow down the application).
• Angle
  This property allows you to define the angles in which the particles will be created. Note that the chosen angle is modified by applying the next property.
• Angle interval
  Once the angle has been chosen using the previous property, a random number is generated, ranging from -“Angle interval” to +”Angle interval”, and this number is added to the angle. As a result, the particles will be spread in a portion of circle (depending on how big this value is).
• Initial speed
  This property contains the speed of the created particles. The speed will be modified by the next property.
• Speed interval
  As for the angle, a random number is generated ranging from -“Speed interval” to +”Speed interval”, and added to the value of the speed property. As a result, the speed of the created particles will be different depending on the value of this property.
• Initial torque
  This property contains this initial torque of the particle. If non-zero, the particles will rotate at a constant pace. Value range: from -250 (clockwise, very fast) to 250 (anti clockwise, very fast). Values like 10 are usually chosen for good effects.
• Applied force
  This property contains a force that is applied constantly to each particle, making it accelerate (for positive values), or decelerate (for negative values).
• Applied torque
  This property contains a torque to be applied to the created particles, making them accelerate their rotation as they move. Value range: from -250 (clockwise, very fast) to 250 (anti clockwise, very fast).
• Particle images
  This property contains a list of images used to display the particles. You can define up to 32 different images. The images will be played in sequence at the speed defined by the next property.
• Animation speed
  This property contains the speed of the animation of the particles.
• Loop animation
  If checked, the animation of the particle will restart at the first image when the end is reached.
• Scale
  This property allows you to increase or reduce the size of the particles. The particles will keep the same size if the property is set to 0, they will grow if the property is over 0 and shrink if it is below 0.
  Warning : collision detection with the particles will NOT work if the particle size changes constantly. It will only work with a value of 0 in this property.
• Friction
  This property contains the friction parameter of the created particles. A friction of 0 will make your particles slide on all the other objects, a value of 100 will make them stick to the other objects.
• Elasticity
  This property contains the elasticity parameter of the created particles. A value of 0, and the particle will not bounce at all when colliding with other objects. A value of 100 and they will bounce forever.
• Density
  This property contains the density of the object. A higher value will make your particles heavier (they will have more effect on the other objects). A value of 30 is usually used.
• Gravity factor
  This property contains the percentage of the world’s gravity to apply to the created particles. A value of 0 will make your particles float in the air. A negative value will make them go in the reverse direction of the world’s gravity.
• Engine ID
  This property contains the identifier of the Physics – Engine object to use, if you decide to use more than one object on the frame.

The Conditions

• A particle collides
  • With a backdrop
    This condition is true when a particle collides with a backdrop from the world. You can choose to destroy the particle or stop it for example.
  • With another particle
    This condition is true when two particles collide.
  • With another object
    This condition is true when a particle collides with another object of the world.
• A particle leaves the frame
  • On the left
    This condition is true when a particle leaves the frame area on the left. You can choose to stop the particle, or destroy it.
  • On the right
    This condition is true when the particle leaves the frame on the right.
  • On the top
    This condition is true when the particle leaves the frame on the top.
  • On the bottom
    This condition is true when the particle leaves the frame on the bottom.
• On each particle
  This condition is called when you perform a “For each particle” action. It is called for every one of the particles on the screen.

The Actions

• Stop particle
  Stops the movement of the current particle. Use this action in a collision detection event.
• Create / Destroy
  • Create particles
    This action creates a given number of particles, all at once, using the current parameters as defined in the properties of the object, or modified with actions.
  • Destroy particle
    Destroys the current particle.
  • Destroy both particles
    Use this action in an event beginning by a “A particle is colliding with another particle” condition. It will destroy both particles.
• Particles
  • Set animation speed
    Changes the speed of the animation of the newly created particles (the ones already created will not change).
  • Set animation loop ON/OFF
    Change the loop flag of the newly created particles.
  • Set particle scale
    Changes the scale factor of the newly created particles.
  • Set friction
    Changes the friction of the newly created particles.
  • Set elasticity
    Changes the elasticity of the newly created particles.
  • Set gravity scale
    Changes the gravity scale of the newly created particles.
• Particle creation
  • Set automatic creation ON/OFF
    Turns on or off the automatic creation of the particles. You will have to use the “Create particle” action to create particles if this option is turned off.
  • Set particle initial speed
    Changes the speed of the particles when they are created. Note that the parameter of the next action is used to modify the speed, as explained in the Properties page.
  • Set particle speed interval
    Changes the interval of speed used when creating a particle. Please look at the Properties page of this documentation for more explanation.
  • Set particle initial angle
    Changes the angle of the particles. This action waits for an angle expressed in degrees (0 – 360). Note that the next action will also modify the angle.
  • Set particle angle interval
    Changes the angle interval used to calculate the angle of creation of the particles. Please read the Properties page of this documentation for more information.
  • Set particle initial torque
    Changes the torque applied to the particles when they are created. The value can range from -250 (clockwise) to 250 (anti-clockwise)
  • Set force applied to particles
    Changes the constant force that is applied to each particle during its life. Changing this value will have an instant effect on all the particles.
  • Set torque applied to particles
    Changes the constant torque applied to each particle during its life. Changing this value will have an instant effect on all the particles.
• For each particle
  • Start loop
    Starts a loop that explores each one of all the particles active in the world at the moment it is called. You must use a “On each particle” condition as the first condition of the events where you want to affect the particles. This action waits for a parameter containing the name of the loop.
  • Stop loop
    Stops the current loop if it was running.

The Expressions

• Number of particles
  Returns the number of particles active at this moment in the world.
• Particles
  • Get particle X coordinate
    Returns the horizontal coordinate of the current particle.
  • Get particle Y coordinate
    Returns the vertical coordinate of the current particle.
  • Get particle angle
    Returns the angle, in degrees, of the current particle.
• Particle creation
  • Get particle initial speed
    Returns the speed at which the particles are created.
  • Get particle speed interval
    Returns the random interval added to the speed when creating a particle.
  • Get particle initial angle
    Returns the angle in degrees in which the particles are created.
  • Get particle angle interval
    Returns the angle interval used to calculate the final angle in which the particles are created.
  • Get particle initial rotation
    Returns the value of the torque used to created the particles.
  • Get particle applied force
    Returns the value of the force that is applied to each particle during its life.
  • Get particle applied torque
    Returns the value of the torque that is applied to each particle during its life.
• Get particle loop index
  Returns the index of the particle when in the middle of a “For each particle” loop.