Creating & configuring particle systems in Reality Builder

Tutorial Authors:Clifton Poli, Jesse Rapczak

Artist-driven particle effects in Reality Builder:

Precipitation

Introduction

Reality's precipitation particle system allows the user to create realistic weather effects such as rain, sleet, hail, and snow to add realism and atmoshere to the environment. This system has a short learning curve, following is a list of its properties which will familiarize you with it. To place the rain script into your scene you need to click on the script dropdown list and select 'Precipitation' then click on the Insert button.

Properties

• AccelX/Y/Z
  • The X/Y/Z component of particle acceleration used after emittance (such as gravity)

• AdjustByDayTime
  • Whether the object adjusts its intensity according to the time of day, using its TurnOnTime/TurnOffTime values.

• Color Components
  • ColorAlpha: This controls the opacity of the rain, range is 0-255
  • ColorBlue: 0-255
  • ColorGreen: 0-255
  • ColorRed: 0-255

• DestBlendMode
  • Mode of destination blending used on the particles. There is 13 different blend modes, however most of them are just wierd, so here are the most usefull ones listed below.
    • MBLEND_NONE: No blending of course!
    • MBLEND_ZERO: Subtractive blending (color subtraction, becomes darker) This could be useful for effects such as smoke.
    • MBLEND_ONE: Additive blending (color addition, becomes lighter) This is usefull for creating emissive stuff like sparks, fire, etc.
    • MBLEND_INVSRCCOLOR: lighter colors will become opaque, darker colors more translucent
    • MBLEND_DESTALPHA: Alpha blending (white alpha channel equals opaque)

• FollowCamera
  • This lets you set if the precipitation actor follows the camera around or if its stationary. This is usefull for looking at the effect in different ways for tweaking.

• Height
  • Height above the camera (for when FollowCamera is set to true)

• ImpactDensity
  • Surface impact density (splashes etc.) Very CPU Intensive! Range is 0-100

• LitBySky
  • Whether the particle system's color is multiplied by the sky light color, useful for non emiisive outdoor particle systems.

• NumParticles
  • How many particles are used in the system

• ParticleColor
  • Color of the particles (multiplied by the texture)

• ParticleDirVariance
  • The % of spherical spread of the particle emittance direction. 0 will shoot particles exactly in the rotation of the emitter, 1 will shoot them in all directions.

• ParticleLifeTime
  • The base lifetime in milliseconds of each particle.

• ParticleLifeTimeVariance
  • A random amount of milliseconds added to the base lifetime for each particle, from 0 to the specified value.

• ParticleSize
  • Base size of each particle in meters.

• ParticleSizeVariance
  • A random size in meters subtracted from the base ParticleSize for each particle, subtracted from 0 to the specified value (often is about 1/3rd of the ParticleSize).

• ParticleSpeed
  • Speed of particles in meters.

• ParticleSpeedVariance
  • A random speed in meters added onto the base speed for each particle, from 0 to the specified value.

• ParticleTextureFileName
  • The texture file used for the system's particles.

• ParticleTimeFadeOut
  • The amount of milliseconds that a particle fades out for. Shouldn't be greater than the ParticleLifeTime (often is about 1/3rd the particleLifeTime)

• PosVarianceX/Y/Z
  • Particle spawn variance along the X, Y, and Z axis

• PreventIndoors
  • Prevent individual particles from going indoors.

• SkyLitAmount
  • Percentage of the particles color that is lit by the sky. This allows the particle to bias against the sky lighting during sky color extremes (such as dusk).

• SpawnInterval
  • The interval in milliseconds between particle spawns.

• TurnOFF/ON/Hours/End/Start
  • These settings determine the time of day that the actor activates and when it turns off

• YAxisConstraint
  • Amount to constrain particle along Y axis (so it doesn't always face you). Range is 0-2.

Volumetric Light effects

Introduction

Reality's Volumetric Light effects system allows the user to create a wide array of different light effects, such as light beams on vehicles, flashlights, and volumetric effects from lights in a scene. To place the script into your scene you need to click on the script dropdown list and select 'Effect_LightBeam' then click on the Insert button. Then move and rotate the actor into the desired position. The light beam can also be attached to a light in the scene and even take on that lights trasform, so that the effect will match the movements of the light, the light beam will also make use of that lights time of day settings.

Properties

• AttachedLightName
  • Light name, if any, to attach to. Beam will take its hidden state and intensity from the Attached Light, and destroy itself if the Attached Light is destroyed.

• ColorComponents
  • ColorAlpha, Blue, Green, Red, 0-255 range for each.

• DistanceMultiplier
  • Spread between billboards, in meters.

• GlowTextureFileName
  • The texture file used for the light beam's billboards.

• NumUnits
  • Number of light beam billboard units (also determines length of beam in tandem with the DistanceMultiplier).

• StartSize
  • Starting billboard size.

• SizeMultiplier
  • Increase in size per billboard down the beam.

• TotalScalingFactor
  • Scales the entire system by the specified amount.

• TransformFromAttach
  • Whether the Light Beam also takes its transformation (Location and Direction) from the Attached Light, if any.

Particle System

Introduction

Reality's Particle effects system allows the user to implement a variety of phenomena such as steam, smoke, sparks, atmospheric effects, etc, with just a few parameter changes. To place the script into your scene you need to click on the script dropdown list and select 'Effect_ParticleSystem' then click on the Insert button. Then move and rotate the actor into the desired position. Particles emit in the direction of the system.

Properties

• AccelX/Y/Z
  • The X/Y/Z component of particle acceleration used after emittance (such as gravity)

• Color Components
  • ColorAlpha: This controls the opacity of the particles, range is 0-255. Is multiplied by the alpha channel if MBLEND_INVSRCALPHA is selected as the blend mode
  • ColorBlue: 0-255
  • ColorGreen: 0-255
  • ColorRed: 0-255

• DestBlendMode
  • Mode of destination blending used on the particles. There is 13 different blend modes, however most of them are just wierd, so here are the most usefull ones listed below.
    • MBLEND_NONE: No blending of course!
    • MBLEND_ZERO: Subtractive blending (color subtraction, becomes darker) This could be useful for effects such as smoke.
    • MBLEND_ONE: Additive blending (color addition, becomes lighter) This is usefull for creating emissive stuff like sparks, fire, etc.
    • MBLEND_INVSRCCOLOR: lighter colors will become opaque, darker colors more translucent
    • MBLEND_DESTALPHA: Alpha blending (white alpha channel equals opaque)

• LitBySky
  • Whether the particle system's color is multiplied by the sky light color, useful for non emiisive outdoor particle systems.

• NumParticles
  • How many particles are used in the system

• ParticleColor
  • Color of the particles (multiplied by the texture)

• ParticleDirVariance
  • The % of spherical spread of the particle emittance direction. 0 will shoot particles exactly in the rotation of the emitter, 1 will shoot them in all directions.

• ParticleLifeTime
  • The base lifetime in milliseconds of each particle.

• ParticleLifeTimeVariance
  • A random amount of milliseconds added to the base lifetime for each particle, from 0 to the specified value.

• ParticleSize
  • Base size of each particle in meters.

• ParticleSizeVariance
  • A random size in meters subtracted from the base ParticleSize for each particle, subtracted from 0 to the specified value (often is about 1/3rd of the ParticleSize).

• ParticleSpeed
  • Speed of particles in meters.

• ParticleSpeedVariance
  • A random speed in meters added onto the base speed for each particle, from 0 to the specified value.

• ParticleTextureFileName
  • The texture file used for the system's particles.

• ParticleTimeFadeOut
  • The amount of milliseconds that a particle fades out for. Shouldn't be greater than the ParticleLifeTime (often is about 1/3rd the particleLifeTime)

• PosVarianceX/Y/Z
  • Particle spawn variance along the X, Y, and Z axis

• PreventIndoors
  • Prevent individual particles from going indoors.

• SkyLitAmount
  • Percentage of the particles color that is lit by the sky. This allows the particle to bias against the sky lighting during sky color extremes (such as dusk).

• SpawnInterval
  • The interval in milliseconds between particle spawns.

• YAxisConstraint
  • Amount to constrain particle along Y axis (so it doesn't always face you). 0-2