Release from Data File

Use a 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: , , , and .

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

your computer to select a text file, then click to import the data. To remove the imported data, click . Enter the 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 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 α, β, and γ (in 3D) or the 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 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 list: (the default), , , , , or (3D only).

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For , enter the 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 section, select the 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 the check box is selected under the physics interface section.

Select a : (the default), , , , , or .

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When is selected, enter the . 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 nodes in the model, choose an option from the list: , (the default), , , , or .

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When is selected, enter the . 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.