Module: Pathlines ()

Description:

This module computes pathlines in 3D time dependent vector fields. Pathlines are traces of massless particles in the time dependent vector field.

This module only works for vector fields with a time-independent grid, and only if physical time information is available.

By default, particles are seeded at random locations within a 3D axis aligned box. Alternatively, a vertex set can be provided to use as seeding particles.

The computation result is a line set with particle traces. The first data column records the integration time of each particle.

The vector field data of all selected time-steps are loaded into the main memory. It is in the responsibility of the user to ensure that the selected range does not exceed available resources.

Connections:

Data [required]
The time dependent vector field the pathlines are computed for.

Distribution [optional]
Either a vertex set that is used as seed particles, or a ROI (region-of-interest) module for selecting the box for random seeds.

Ports:

Display

Mode for automatic display.

Time Options

Mode

Integration start time and end time can either be chosen by
ordinal: the ordinal number of loaded time steps, started by 0,
physical: the physical time, or
time step: the time step.

Start

Start time of the integration. Particles are seeded at the start time.

End

End time of the integration.

Physical start

Start time of the integration. Particles are seeded at the start time.

Physical end

End time of the integration.

Step Start

Start time of the integration. Particles are seeded at the start time.

Step End

End time of the integration.

Step size

Step size for the integration and distances of the adjacent vertices in the resulting line set. This value will be multiplied with the diameter of the field's bounding box.
This parameter also controls the numerical accuracy of pathline integration.

Seed Options

Amount

Number of particles if in random seed mode.

Value

Seed value for the random number generator. If non 0, results of random seeding are reproducible.

Bounding box

Clicking on XformBox or TabBox brings up a 3D dragger in the 3D Viewer. This allows you to restrict the region of interest, i.e. the region in which seed points are placed, by interactively transforming the dragger (Remember to switch the viewer into interaction mode by pressing ESC). After changing the box, you must press Apply to trigger recalculation.