The Arrow source can be used to add a polygonal arrow to the 3D scene. The arrow consists of a cylinder for the shaft, and a cone for the tip. By default the arrow has an origin at (0,0,0), has a length of 1.0, and is pointing along the positive x axis. The arrow can be translated, rotated, and scaled using the Actor control area of the Display tab for this source, and it can be interactively positioned using the Move operation of the camera. The object created by this source is a vtkArrowSource object, and the output of this source is vtkPolyData. An example of an Arrow source is given below.
The Arrow source has the following parameters:
Tip Resolution: This is the number of faces around the cone representing the tip of the arrow. A larger number will mean a smoother cylinder but more polygons which can lead to slower rendering times. The default value is 6 which is fairly coarse.
Tip Radius: This is the radius of the cone defining the tip of the arrow. The length of the whole arrow is 1.0 unit. By default the tip radius is .1 unit.
Tip Length: This is the length of the tip of the arrow, and should be a number greater than 0.0 and less than 1.0. The total length of the arrow is 1.0 unit, so if the tip length is set to 0.25, then the shaft cylinder will be 0.75 units long. The default value is 0.35.
Shaft Resolution: This is the number of faces around the cylinder representing the shaft of the arrow. The default value is 6.
Shaft Radius: The is the radius of the cylinder defining the shaft of the arrow. The default value is 0.03.
The output polydata from the Arrow source will not contain normals, therefore rendering of the arrow will be performed using flat shading. The appearance of the arrow can be improved without significantly increasing the resolution of the tip and shaft by generating normals.