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Class ParticleTraceGroup

Specification of a particle trace group (both parameters and attributes) in a RemoteModel.

To visualize features of a vector field, it is possible to define streamlines: the paths of massless particles through the flow. Streamlines can be computed based on the specification of single points. Animating the movement of particles along these streamlines gives a powerful and direct tool for visualizing the features of a flow.

Particle traces are defined by a vector result specifying the vector field and an array of trace seed points. The particles traces use 3D primitives such as cylinders, spheres, or comets to visualize the traces. A scalar result can be mapped as fringes onto these primitives.

Particle traces can be animated. All particle trace groups must have the same number of animation steps. You specify this with Animation.particleTraceAnimationStepCount. You can start the animation with Animation.runParticleTraceAnimation.

To create a particle trace group, use RemoteModel.addParticleTraceGroup.

Example: Show a grid of traces

  var modelDir = myModel.modelDirectory;

  // Create a grid of 10x10 points to use a seed points
  var center = new cee.Vec3(-0.017, -0.00726, 0.0016);
  var seedPoints = cee.ug.ParticleTraceUtils.computeGridPoints(center,
                   new cee.Vec3(1,0,0), 10, 10, 0.0005);

  // Create the particle trace group
  var ptGroup = myModel.addParticleTraceGroup();
  ptGroup.seedPointArray = seedPoints;
  ptGroup.vectorResultId = modelDir.vectorResultArray[0].id;
  ptGroup.mapScalarResultId = modelDir.scalarResultArray[0].id;
  ptGroup.radius = 0.00015;

  // Set model to outline to show the cutting planes

This code sample produces the following image in the 3D Viewer:

alt text


  • ParticleTraceGroup




color: Color3Like

The color of the particle traces. This property only applies if mapScalarResultId is set to -1.

The default is white (1,1,1)


extrapolateRatioLength: number

The ratio length relative to the frame bounding box to test when moving out of the part

This controls how far to extrapolate the particle trace when leaving a part and entering another part The Ratio is given as a fraction of the bounding box of the current frame.

Readonly id

id: number

The id of the particle trace group. This is assigned by the system when you call RemoteModel.addParticleTraceGroup and is used to identify the group.

Readonly isPrecomputed

isPrecomputed: boolean

Is true if the particle trace group is precomputed and cannot be changed


mapScalarResultId: number

The id of the scalar result to show on the particle traces.

This id must refer to one of the scalar results in ModelDirectory.scalarResultArray. You can change the settings for the scalar with the ScalarSettings object.

Set to -1 to show no scalars on the traces. In this case the value of color will be applied.


massedParticleParameters: MassedParticleParameters | undefined

Massed particle trace parameters.

If these paramers are set (not undefined), the particle traces will be computed based on massed particles with the given properties.


pointSamplingPulseCount: number

Spheres and comets are emitted at regular intervals. This value specifies how many pulses there should be in the model.

The default is 5.


radius: number

The radius of the particle trace geometry (cylinder, sphere, comet), in world coordinates.

The default is 0.005 of the extent of the bounding box.


relativeCometLength: number

The length of the tail of the comets. It is specified in time and is a fraction of the global total time range for all particles in this group.

For example, if the total trace time is 2, and the relativeCometLength is 0.01, then the length of the tail will be 0.02.

The default is 0.1


seedPointArray: ReadonlyArray<Vec3Like>

An array of seed points. Each point will result in a particle trace going through the point. If traceBothDirections is set to true, the trace will be computed both forwards and backwards from this point. If it set to false, only the forward computation will be done. All traces share the same settings, as defined by other properties of the ParticleTraceGroup.

You can use the ParticleTraceUtils.computeGridPoints static function to generate a grid of points based on a point and normal.


traceBothDirections: boolean

If set to true, the trace will be computed both forwards and backwards from the seed point(s).

If set to false, the trace will only be computed forwards from the seed point(s).


vectorResultId: number

The vector result to compute the traces in. This property is mandatory and must refer to one of the vector results in ModelDirectory.vectorResultArray.


visible: boolean

Visibility of the particle trace group. Use this to show or hide a particle trace group in the 3D Viewer.


The visualization type to use for the particle traces. This can be set to cylinders, spheres or comets.




  • Applies the settings in the given properties object to this particle trace group


    Returns void

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