Intersection Point 2D and Intersection Point 3D
Use an Intersection Point 2D () or Intersection Point 3D () dataset, found under the More 2D Datasets and More 3D Datasets submenus, to enable evaluation of expressions at the intersection points of particle or ray trajectories and a surface or to evaluate intersection points with a more general surface. You can use the Intersection Point datasets with the following plot nodes and derived value nodes: Particle Trajectories and Ray Trajectories; Particle and Ray (1D plots); Particle Evaluation and Ray Evaluation; Point Trajectories; Histogram; Phase Portrait; Optical Aberration; and Aberration Evaluation.
Go to Common Results Node Settings for links to information about this section: Data. The dataset must point to a Particle or Ray dataset. For information about the Extra Time Steps section, see Extra Time Steps for Trajectory Plots and Intersection Point Datasets,
Curve
This section is only available for Intersection 2D datasets.
From the Curve type list, you can specify that the intersection of the particle or ray trajectories with one of the following curves is taken:
Line (the default)
For each of these surface types, additional settings are available.
Line
For Line as the curve type, choose one of the following options from the Line entry method list:
If you choose Two points, enter the coordinates of the two points that define the line in the x and y columns for Point 1 and Point 2. If you want the line to be bounded by the points instead of extended beyond both points, select the Bounded by points check box (selected by default).
If you choose Point and directions, enter the x and y coordinates for a point under Point and the x and y components of a direction vector under Direction.
If you want to create additional lines that are parallel to the line you defined, select the Additional parallel lines check box and enter the distances between each line in the Distances field, or click the Range button () to define a range of distances.
Circle
For Circle as the curve type, you define the circle by entering its center coordinates in the x and y fields under Center and the radius in the Radius field.
Semicircle
For Semicircle as the curve type, you define the semicircle by entering its center coordinates in the x and y fields under Center, an axis direction in the x and y fields for the axis vector components under Axis direction, and the radius in the Radius field. The axis direction defines the extent of the semicircle as the segments of the circle perimeter where the scalar product with the axis direction vector is positive. For example, with the default axis direction (0, 1), the semicircle consists of the circle perimeter where y > 0.
General
For defining a general curve, you enter a curve expression F(r). The intersection points will be evaluated on the curve F(r) = 0.
Surface
This section is only available for Intersection 3D datasets.
From the Surface type list, you can specify that the intersection of the particle or ray trajectories with one of the following surfaces is taken:
Plane (the default)
For each of these surface types, additional settings are available.
Plane
For Plane as the surface type, choose one of the following options from the Plane type list:
If you choose General (the default), see the settings for the available plane entry methods below.
If you choose Quick, you can choose one of xy-planes, yz-planes, zx-planes, yx-planes, zy-planes, or xz-planes from the Plane list. Depending on the selected plane’s orientation, you can enter the x-coordinate, y-coordinate, or z-coordinate as an offset for the plane (default: 0).
For a General plane type, also choose one of the following options from the Plane entry method list:
If you choose Three points, enter the coordinates of the three points that define the plane in the x, y, and z columns for Point 1, Point 2, and Point 3.
If you choose Point and normal, enter the x and y coordinates for a point under Point and the x and y components of a direction vector under Direction.
If you want to create additional surfaces (planes) that are parallel to the plane you defined, select the Additional parallel planes check box and enter the distances between each plane in the Distances field, or click the Range button () to define a range of distances.
Sphere
For Sphere as the surface type, you define the sphere by entering its center coordinates in the x, y and z fields under Center and the radius in the Radius field.
Hemisphere
For Hemisphere as the surface type, you define the hemisphere by entering its center coordinates in the x, y, and z fields under Center, an axis direction in the x, y, and z fields for the axis vector components under Axis direction, and the radius in the Radius field. The axis direction defines the extent of the hemisphere as the parts of the sphere’s surface where the scalar product with the axis direction vector is positive. For example, with the default axis direction (0, 0, 1), the hemisphere consists of the part of a full sphere where z > 0.
General
For a general surface, you enter a surface expression F(r). The intersection points will be evaluated on the surface F(r) = 0.
Advanced
Under Space variables (Intersection Point 3D only), you can change the name of the space variables x and y for the intersection surface’s coordinates from their default values (ip1x and ip1y, for example).
Under Normal variables, enter or edit the variable names for the components of the normal vector — nx, ny, and nz (Intersection 3D) or nx and ny (Intersection Point 2D). The default names are ipl1nx, ipl1ny, and ipl1nz, respectively.
Select an option from the Interpolation between time steps list: Linear (the default) or Cubic. If the expressions being evaluated at the intersection point are differentiable, the Cubic interpolation method will take into account the derivatives of these expressions at the time steps before and after the intersection point is reached. This allows expressions that do not vary linearly over time to be interpolated more accurately.
Intersection 2D and Intersection 3D datasets require the Particle Tracing Module or the Ray Optics Module.