Rotation of Streamlines
The AngularVelocity and Rotation fields generated by VTK for streamlines have a wrong scale. If you make a Ribbon, they rotate with the wrong speed. In general angular velocity should be computed as half of Vorticity.
VTK provides a "Rotation Scale" parameter. But it is not accessible in ParaView. Setting it to
-0.5 would get the right Rotation (and right Normal vector for Ribbon).
It is sufficient to add:
<DoubleVectorProperty command="SetRotationScale" default_values="1" label="Rotation Scale" name="RotationScale" number_of_elements="1" panel_visibility="advanced"> <DoubleRangeDomain name="range" /> <Documentation>Scale applied to Vorticity to get AngularVelocity and Rotation</Documentation> </DoubleVectorProperty>
vtkStreamTracer proxies in
Then the "Rotation Scale" will be accessible, and can be set to
-0.5 (maybe this should be default?)