Appendix: Particle Property Overlays

The SC2Particles and SC2Ribbons have a unique feature for some parameters, Property Overlays. In general SC2Particles have a simple random range for most values. Property Overlays are a way to add more unique animation ability quickly to these kinds of effects. This will alter the property at particle creation time with a procedural offset value, and will remain constant for the life of each particle. The value is controllable with a simple set of curve types as well as animatable values for amplitude, and frequency.

SC2Particle Properties that allow Overlays

Next to some of the SC2Particles properties is a small UI button that is blank by default. If there is an overlay applied the box will show an O on the button.

• Yaw Overlay will give a procedural offset to the initial particle direction in the local X axis.

• Pitch Overlay will give a procedural offset to the initial particle direction in the local Y axis.

• Vert Spread Overlay will give a procedural offset to the random range of the particle initial direction of travel on the Vertical axis.

• Horz Spread Overlay will give a procedural offset to the random range of the particle initial direction of travel on the Horizontal axis.

• Speed Overlay will give a procedural offset to the initial Speed of particles.

• Alpha Overlay will add an offset to the particle alpha values.

• Rotation Overlay adds an offset to the particle rotation. The amplitude value is in radians and not degrees.

• Size Overlay adds an offset to the particle scale.

SC2Particle Property Overlay Pop-Up

By clicking the overlay button, a Pop-up window will appear where you can modify the values for the Property Overlay.

1. Curve Type: is a pulldown to select the animation curve type.

   • None default and no Overlay applied. To clear an Overlay, set it to None.

   • Sin applies a smooth Sine Wave animation offset.

   • Cos applies a smooth Cosine Wave animation offset.

   • Saw Tooth applies a linear offset that starts at negative amplitude and increase to positive amplitude over one frequency cycle and then starts again at negative amplitude.

   • Square Wave offset alternates between negative and positive amplitude.

   • Random Noise picks a random value from negative amplitude to positive amplitude.

   • Continuous Noise is a moving random value that will be a similar offset to particles created before and after that moment in time. The nature of this moving average noise type, is that amplitude values need to be 2 to 4 times larger than other Curve Types.

2. Amplitude: is the offset value to be applied. An Amplitude value of 1 will yield a value from -1 to +1 that will be added to the particle property at the moment of creation.

3. K is the active Key frame button. These buttons will show red when the Amplitude or Frequency has an active key frame at the current time. Click to add or remove a key frame from the current time.

4. Frequency: is the number of cycles per second. The smaller the number, the slower the offset cycling.