Release from Data File
Use a Release from Data File node to specify the initial ray position, direction, and values of auxiliary dependent variables using data from a text file.
See Release for information on the following sections: Release Times, Initial Phase, Initial Intensity, Initial Radii of Curvature, Total Source Power, and Initial Polarization.
Formatting Guidelines for Files Containing Ray Data
The imported data file should be a text file (*.txt) arranged in a spreadsheet format; that is, each row corresponds to a distinct ray and should have the same number of columns as all other rows. Columns can be separated by spaces, tabs, or a combination of the two. Begin a line with the percent (“%”) character to include comments or empty lines in the data file.
For example, a data file containing the following text would release rays at the positions (0.1, 0.2, 0.6) and (0.2, 0.4, 0.8) in a three-dimensional geometry:
% Ray release positions
% qx0 qy0 qz0
0.1 0.2 0.6
0.2 0.4 0.8
Initial Position
Browse your computer to select a text file, then click Import to import the data. To remove the imported data, click Discard. Enter the Index of first column containing position data i to indicate which column represents the first coordinate of the ray position vectors. The default value, 0, indicates the first column.
Transformations
The distribution of loaded ray release positions may be scaled, rotated, and translated before the rays are released.
To scale the distribution of release positions, enter a value or expression for the Scale factor R (dimensionless). The default is 1. This scale factor can be used to correct unit discrepancies between the data file and the model geometry. For example, if the geometry length unit is in meters but the data file lists coordinates in millimeters, enter a scale factor of 0.001.
To rotate the distribution, enter the Euler angles (Z-X-Z) α, β, and γ (in 3D) or the Rotation angle α (in 2D). The default values are all 0.
In 3D, α is the rotation angle about the space-fixed z-axis, then β is the rotation angle about the transformed x-axis (or x’-axis), and finally γ is the rotation angle about the transformed z-axis (or z’’-axis). Positive values indicate counterclockwise rotations.
Enter values or expressions for the components of the Displacement vector Δq (SI unit: m). The default is not to apply any translation.
If a translation and another type of transformation (scaling or rotation) are applied, then the translation is always applied after the other transformations.
Ray Direction Vector
Select an option from the Ray direction vector list: Expression (the default), From file, Spherical, Hemispherical, Conical, or Lambertian (3D only).
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For From file, enter the Index of first column containing direction data i. The default is 3. The columns are zero-indexed; that is, an index of 0 corresponds to the first column. If you chose to rotate the loaded ray release positions in the Initial Position section, select the Rotate initial directions check box to apply the same rotation to the initial direction of the released rays. The check box is cleared by default.
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For all other settings, the settings are the same as for the Release node.
Initial Ray Frequency
This section is available when Polychromatic, specify frequency is selected from the Wavelength distribution of released rays list in the physics interface Ray Release and Propagation section.
Select a Distribution function: None (the default), Normal, Lognormal, Uniform, List of values, or From file.
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When From file is selected, enter the Index of column containing frequency data. The default value is 3. The columns are zero-indexed; that is, an index of 0 corresponds to the first column.
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For all other options, the settings are the same as for the Release node.
Vacuum Wavelength
This section is available when Polychromatic, specify vacuum wavelength is selected from the Wavelength distribution of released rays list in the physics interface Ray Release and Propagation section.
Select a Distribution function: None (the default), Normal, Lognormal, Uniform, List of values, or From file.
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When From file is selected, enter the Index of column containing wavelength data. The default value is 3. The columns are zero-indexed; that is, an index of 0 corresponds to the first column.
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For all other options, the settings are the same as for the Release node.
Initial Value of Auxiliary Dependent Variables
This section is available if an Auxiliary Dependent Variable has been added to the model.
For each of the active Auxiliary Dependent Variable nodes in the model, choose an option from the Distribution function list: From file, None (the default), Normal, Lognormal, Uniform, or List of Values.
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When From file is selected, enter the Index of column containing data. The default value is 3. The columns are zero-indexed; that is, an index of 0 corresponds to the first column.
For all other options, the settings are the same as for the Release node.