Mode

Not interactive is the default. This doesn’t calculate the particle animation until you move to a different frame (either by clicking the Play button below the timeline or moving the playback cursor). This lets you choose when you want to play back the simulation, especially if your system is a bit slow and you don’t want to wait for each update to be calculated.

Interactive recomputes the animation from start frame as soon as you modify a particle parameter. This is useful for immediately seeing the effects of your changes.

Disconnected doesn’t calculate the particle animation at all. This is useful for setting parameters and moving back and forth on the timeline without having to wait for the particle simulation to update.

Start Frame

Initial frame of the simulation

Duration

Number of frames of the simulation

Copy from Scene

Copies the start and end frame values from the scene’s timeline to the Start Frame and Duration.

Copy to Scene

Copies the values you set for the Start Frame and Duration to the scene’s start and end frame values on the timeline.

Time Scale

Scales the dynamic with respect to time. If, for example, you divide this value in half, the whole dynamic evolves at twice the speed.

Space Scale

Scales the dynamic with respect to spatial dimensions. Modifying this parameter changes the space extension of the explosion without changing its shape.

Particles %

Percentage of the particles that are emitted. Setting this to a lower value is useful for a quick preview of the particles’ behavior.

Seed

Seed for the pseudo-random-number generator.

Sparks

Activates the sparks phase of the explosion. You can set the spark structure’s parameters on the Sparks page (see Sparks), as well as select and edit the particle type to use.

Smoke

Activates the smoke phase of the explosion. You can set the smoke structure’s parameters on the Smoke page (see Smoke), as well as select and edit the particle type to use.

Flame

Activates the flame phase of the explosion. You can set the flame structure’s parameters on the Flame page (see Flame), as well as select and edit the particle type to use.

Output Sequence

Directory and path name for the output particles files (a .ptp is generated for each frame). By default, the name is Explosion plus an instance-counter number. If Usr is on, the path is displayed as you entered it. If Res is on, the resolved path is displayed.

Clean Cached Files

When you exit XSI, this deletes the .ptp files that were recorded and cached for the particle simulation in the current session.

Use File for Rendering

Activates a flag that tells the Explosion shader to use the PTP files currently specified in the Output Sequence for rendering the simulation. This option is useful if you’re rendering over a number of machines and you want each machine to use the same PTP files as they render the same simulation.

Iterations

When a particle collides with an obstacle, its velocity is modified, which could cause a new collision with a different obstacle. To accurately calculate this, any time a collision is detected Explosion checks if a new collision can occur with all the remaining obstacles, iterating this process until no more collisions can be detected. This parameter sets the maximum number of iterations that occur inside a single time step. The higher the number, the more accurate the collision detection (at the cost of more time).

Interframes

Sets the number of interframes in which a single frame has to be subdivided for collision detection. The higher the number, the more accurate the collision detection (at the cost of more time).

Check Particles

Detects collisions between particles and obstacles and calculates how the particles will respond. If this option is off, only collisions with structures are detected.

ParType

Name of particle type to use for the emission (smoke, sparks, or flame, by default). Click the New button to create a new particle type, or click the Edit button to open the particle type’s PType (Particle Type) Property Editor.

Emission

Defines the type of emissions used for each structure (flame, smoke, or sparks): structures, particles, structures+flame particles, structures+smoke particles, or structures+sparks particles.

Speed

Defines the reference emission speed in SOFTIMAGE units per second of the structures along the emission direction. The actual emission speed is controlled by this value and the Emission shape.

This parameter also has a Var parameter (see Particle Variance and Seed Parameters) so that you can produce a more random effect on the particles.

Struct. Rate

Defines the rate of structure particles emitted per second.

This parameter also has a Var parameter (see Particle Variance and Seed Parameters) so that you can produce a more random effect on the particles.

Struct. Life

Duration of life (in seconds) of the structure. When the structure dies, all its particles disappear simultaneously.

This parameter also has a Var parameter (see Particle Variance and Seed Parameters) so that you can produce a more random effect on the particles.

Particle Rate

Controls the number of particles emitted per second.

This parameter also has a Var parameter (see Particle Variance and Seed Parameters) so that you can produce a more random effect on the particles.

Buoyancy

The movement (acceleration) of particles in the direction opposite of gravity. This value is the buoyancy coefficient at any frame for the structures. When 0, there is no buoyancy; when 1, the acceleration is equal (or opposite) to gravity, etc. You must have gravity set for the explosion system for Buoyancy to have an effect.

This parameter also has a Var parameter (see Particle Variance and Seed Parameters) so that you can produce a more random effect on the particles.

Evolution Time

The number of seconds needed to go from the Start to the End value.

Vorticity

Angular speed in degrees per second of the structure around its normal axis. In regard to the direction of the normal axis, if no point of the icon is tagged, the axis is generated randomly. If some points are tagged, they define some “special” directions; when the structure is created, the normal axis is generated so as to be perpendicular to both the radial axis and the closer “special” direction. The overall effect is that each special direction is surrounded by the structures rotating symmetrically with respect to it and with velocities tangential to itself.

This parameter also has a Var parameter (see Particle Variance and Seed Parameters) so that you can produce a more random effect on the particles.

Gravity Coeff.

The coefficient value used to scale the intensity of gravity.

Air Friction

Amount of air friction between the air and the structures. A value of 0 is no air friction, and 1 is full friction (structures have the same speed as the Wind force). The air resistance is proportional to Air Friction and the difference between the structure’s speed and the wind.

Fading Age %

The starting time of fading in terms of the percentage of the structure’s life. When the structure percentage age reaches this value, the alpha channel of the structure and its related particles start reducing, taking it to 0 at the structure’s death time. Use this parameter to avoid the effect of particles suddenly vanishing from the scene.

Plane Coeff.

When 0, the structure’s circular-velocity terms lie in the normal radial plane. When 1, the motion plane is the normal-binormal one. Any values between 0 and 1 result in intermediate motion planes.

Radius

The ending value of the radius in SOFTIMAGE units defining the structure’s circular-velocity term. The starting radius is always 0 and the time needed to go from the start to end value is defined by the Evolution Time.

Start and End Speed

The start and end value of the angular speed in degrees per second defining the structure’s circular-velocity term. The time needed to go from the start to end value is defined by the Evolution Time.

Speed

Absolute frame, structure age, or constant initial speed.

Life

Structure death time or structure life duration: Duration of life (in seconds) of the particles.

Rate

Controls the number of particles emitted per second.

Buoyancy

Absolute frame or structure age: The movement (acceleration) of particles in the direction opposite to gravity. This value is the buoyancy coefficient at any frame for the structures. When 0, there is no buoyancy; when 1, the acceleration is equal (or opposite) to gravity, etc. You must have gravity set for the particle system for Buoyancy to have an effect.

Angle

Sets the angle jitter in degrees for the structure’s starting directions.

Smoothness

Sets the smoothness of the structure’s starting directions. This parameter has different effects, depending on the implicit object you chose for the explosion (Sphere or Cylinder).

At 1, all the starting directions are generated randomly from the sphere; for the cylinder, it’s inside the cylinder basis.

At 0, the structures are generated only along the sphere icon’s main directions or the cylinder basis points.

At any value between 0 and 1, it represents the ratio of structures with a random starting direction (for the sphere) or random emission points (for the cylinder) with respect to the total number of structures generated at any frame.

Emission Factor

Value multiplier in the HSV color space for the light.

Emission Min. and Max.

Sets the minimum and maximum values for the light emission.