surface streamlines

The surface streamlines module is used to produce streamlines on any surface based on its slopes. Streamlines are 3D polylines representing the paths particles would travel based on the slopes of the input surface. The direction of travel of streamlines can be specified to be downhill or uphill for the slope case. A physics simulation option is also available which employs a full physics simulation including friction and gravity terms to compute streamlines on the surface.

The Physics radio buttons allow the user to specify whether streamlines will be computed based on the slopes of the surface only or whether a full physics simulation including friction and gravity terms will be used to compute streamlines on the surface. When Gravity is selected Segments perCell and Order do not apply but additional parameters appear for the module. These are:

Integration Time Step is the time step for the numerical integration of the paths. For typical gravity units (like 32 feet per second-squared) this value is in seconds.

Gravity is the coefficient of gravity for your units. If your coordinate units are feet, the appropriate (default) value would be 32 feet per second-squared.

Viscosity Coefficient (v) is the friction term that depends on velocity.

Drag Coefficient (v2) is the friction term that depends on velocity-squared.

Module Input Ports

• Input Surface [Field] Accepts a data field which must be a surface with elevation data.
• Input Locations Field [Field] Accepts the starting points for each line

Module Output Ports

• Output Field [Field] Outputs the streamlines
• Output Object [Renderable]: Outputs to the viewer.