When tracing surface geodesics, specifies the initial direction of the curve to trace. The starting direction can either be the same for all initial points using the From Parameter option or specified for each point individually using the From Attribute options. The specified attribute must be a 3D vector point attribute on the first input.

When tracing velocity streamlines, specifies the velocity field on the surface to trace. This can be given either as a 3D vector primitive or point attribute on the second input. The velocity field is treated as being piecewise constant inside each primitive.

This specifies the target length of each traced curve. The prescribed length can either be used directly or to scale a per source point specified length attribute.

This specifies whether the Length attribute above is used as the raw length (Do Nothing) or if it should multiply a specified length attribute (Scale by Attribute)

This is a point attribute on the first input specifying the maximum length of the curve traced starting from each point.

Defines an additional rotation of the starting direction or the background velocity field around the surface normal.

When tracing the streamlines of a vector field, the vector field can optionally be treated as a rotationally symmetric multi-vector field. When the streamline enters a new face, tracing continues in the symmetric direction. This makes the field line as smooth as possible.

A safeguard to limit the number of points which make up an individual particle path. Off by default.

When tracing surface geodesics, particle paths can be extended when they hit the boundary by reflection. This options specifies the default behavior of boundary edges, whether paths should terminate when they hit them or reflect and continue. Reflection along the boundary can simulate billiard trajectories.

In addition to boundary edges, a path hitting any edge in this edge group will also terminate.

When tracing surface geodesics, a path hitting any edge in this edge group will reflect.