This command specifies the characteristics of a Sampled spectrum given by wavelength and spectral value pairs. Once created, the spectrum Type cannot be changed.
To create a new spectrum: •Menu > Create > New Spectrum •Toolbar button: •Ctrl + Alt + Z •Right mouse click on the Spectra node in the object tree and select "Create New Spectrum" from the list menu
To edit an existing Sampled spectrum: •Double mouse click on a Sampled spectrum node in the object tree •Right mouse click on a Sampled spectrum node in the object tree and select "Edit/View Spectrum" from the list menu
Values outside of the wavelength range specified by the minimum and maximum sample points are zero. Values inside of the wavelength range which do not correspond exactly to sample points are evaluated by linear interpolation between the two closest sample points. If the option "Randomly according to spectrum" is selected on the Wavelengths tab of a source dialog and the Wavelength Range includes wavelengths outside of the spectrum's sample points, then no rays will be generated at those wavelengths. For example, if the Wavelength Range did not include any wavelengths between the sample points minimum and maximum wavelengths, then no rays would be generated at the source.
By right mouse clicking in the spreadsheet area of a sampled spectrum the user can choose to populate the sample points from three pre-defined types; Photopic response, Scotopic response and user-defined wavelength list.
The Photopic response represents the spectral sensitivity of human vision over a spectral band and is used to convert radiometric units to photometric units.
The Scotopic response represents the spectral sensitivity of dark-adapted human vision.
It is also possible to set a sampled spectrum using the user-defined wavelength list from a source definition.
Wavelength and spectral value pairs can be read directly from a text file by right mouse clicking in the spreadsheet area and selecting "Replace Data With File Data" from the list menu. The file should have a *.dat or *.txt extension and consists of a simple two column list of wavelengths (in microns) and spectral value pairs. An example of the formatting is provided below:
0.37 0 0.38 0.000039 0.39 0.00012 0.4 0.000396 0.41 0.00121 0.42 0.004
Detailed Source - Wavelength Tab
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