Particles
Fields
____________________________________________________________________________________
Fields can be assigned to further influence the behavior of a particle system.
For example, a vortex field can be assigned to create a circular motion for the
particles in a particle system.
Also with fields, parameters can be interactively changed and animated.
____________________________________________________________________________________
Before a field can be assigned to a particle system, it has to be created in
the solid construct menu.
Select group, then click on particle fields. Now make a selection from the
available fields:
- chaos
- shown as a capital C wireframe icon, defines a totally random motion. It is useful for creating chaotic motion or adding small random effects to an existing motion.
- linesink
- shown as a wireframe icon with arrows pointing to a y-axis. Particles in this field will be drawn towards the y-axis of the field. It is useful for creating cylinder-like obstacles (with negative power) in an existing motion.
- noise
- shown as a capital N icon, defines a field with a smooth pseudo-random motion which is predictable and therefore not as chaotic as the chaos field type. This field is useful for changing dull motion into a more interesting (natural) motion.
- sink
- shown as a wireframe icon with arrows pointing to the center, defines a field which pulls particles into its center. It is useful for the simulation of a sink or a black hole, or when used with a negative power for the simulation of a source of explosion.
- spot
- shown as a spot icon. It is used to move particles in the direction in which the spot is aimed. Only particles within the space defined by the spot angle are affected. The spot angle can be interactively changed during simulation.
- turbulence
- shown as a cross, defines a turbulent motion. It is useful for creating natural motion. Can slow the simulation when there are complex calculations.
- uniform
- shown as a wireframe icon with an arrow pointing upwards, defines a directional field. It is used to move particles in a certain direction. The upward direction can be transformed to any direction by transforming the field in the transform menu.
- vortex
- shown as an axis with a circle around it. Arrows on the circle indicatea circular motion. It defines a left rotating field (right rotating with a negative power). Particles in this field rotate around the axis of the field. It is useful for vortex motion, as well as spiral and tornado-like motion (when combined with motion along the axis). Transforming the field into an ellipse will also transform its motion. Only particles within the space defined by the axis and the circle are affected.
- wave
- shown as two arrows pointing up and down, defines a field with a motion which is defined by a timecurve in the animation menu. The default time curve defines an up and down circular motion around the center of the wave field.
To select a field to be the currently active field, the parameters of which can be changed using field parameter boxes.
____________________________________________________________________________________
Particle fields can be positioned, directed and animated in 3D space using the
transform and animation menus (the position and direction of a field in
relation to a particle system can be crucial for the resulting motion of the
particles).
____________________________________________________________________________________
In the particle menu, the field can be assigned to a particle system. A field
can influence the particle system by assigning it to one of the following
dynamic parameters (force, fluid, velocity, and ejection) of the active particle system:
- force fields
- This parameter results in the field acting as a force field on the particles. The particles will accelerate according to their mass.
- fluid fields
- This parameter results in the field acting as a moving fluid with a certain viscosity (a parameter). Particles will follow the motion of the fluid depending on their radius, their mass, and the viscosity of the fluid.
- velocity fields
- This parameter results in the field acting as a velocity field. A velocity field directly modifies the velocity of a particle. This result can be highly unrealistic because the effects of mass, startspeed, and gravity will be overruled, although for certain purposes it is useful because there is a direct control on the motion of the particles. Example: When creating a sink or vortex type of motion for the particles, the result is more predictable when assigning the field to velocity instead of force.
- ejection fields
- This parameter results in the field acting only on the initial
direction when a particle is emitted. For example, a uniform field can be assigned to emit all the particles in a certain direction.
example: assigning a field
To assign fields as force fields to a particle system:
- Click the force fields button. A selection list will appear with all fields
available. Select the desired field by double clicking on its tag name in the
left scroll list (available fields list). The name will then also appear in the
right scroll list (selected fields list).
- Multiple fields can be assigned to a dynamic parameter.
- All assigned fields to a dynamic are displayed in the right list.
- To remove a field from a dynamic parameter, double click on its tag name in the right scroll list (selected fields list).
- Clicking on clear will remove all fields from a dynamic parameter.
- The number of fields assigned is displayed in the data box beside the dynamic parameter name in the particle menu.
____________________________________________________________________________________
Parameters are used to change the effect of the field on all assigned particle
systems. To change the parameters of a field, first select the field using the get
field tag.
Changes made in parameters during simulation can be recorded, for example to
animate the power of a field in time. See the chapter on Simulation and
Recording on how to record and animate field parameters.
This list can be found below the get field tag button.
Upon selecting a field parameter from the field parameter selection list (by
clicking twice on the field parameter name), a parameter box will appear at the
top right of the screen. Field parameter values can be changed by using either the
scroll wheel or step boxes, or they can be typed in.
The following parameters are available with the scroll list for fields:
- power
- This parameter will change the power of the active field.
- frequency
- This parameter will scale the 3D pattern of a noise field.
- seed
- This parameter will change the 3D pattern of a noise field, which results in a different motion.
- gradation
- This parameter will change the gradation of uniform, sink, linesink, and chaos fields. gradation
affects the decrease of the power when farther away from the center of the
field ( a negative power results will increase the power when farther away
from the center of the field).
- angle
- This parameter will change the angle of a spot field.
- spiral
- This parameter will create a spiral effect for a vortex field. It will move the particles in a vortex motion towards the center of the field or away from the center of the field (negative value).
Related topics
