FRED Knowledge Base

Plotting Surface Particulate (Mie) Scatter

As of FRED v9.110, the BSDF plot routines ignore user-selection of “Apply on Reflection” or “Apply on Transmission”.  For most scatter models there is no difference in the BSDF values and so there is no need for designation of a plot in transmission or reflection. ...

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Creating a Class Module

Classes in WinWrap serve much the same purpose as libraries in FRED’s original Enable Basic. User-defined routines can be defined within a class and used to streamline your scripts. The example presented here is based upon examples in the WinWrap Help (in FRED, navigate to...

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Adding Birefringent Materials from Data Files

This knowledge base article describes a FRED script (see attached file) which can be used to add a birefringent material to a FRED document using a data file.  Unlike sampled materials, there is currently no option to add birefringent material data from file through the...

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Applying Importance Sampling Specifications in Script

This knowledge base article describes a method of applying importance sampling specifications to a group of surfaces at once using FRED’s scripting language.  Unlike sources, surfaces, coatings, materials, scatter models, ARN’s and raytrace control sets, scatter importance sampling specifications have no reference node on FRED’s...

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Optimizing for a Target Distribution

This knowledge base article will demonstrate how to use FRED Optimum’s optimization capability to modify a system and achieve a desired irradiance distribution.  The system being modified is a PMMA light pipe.  Six variables control the shape of the light pipe and the optimization merit...

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Retrieving Amplitude-Phase Mask data

This article contains a generic script for reading the contents of an existing Amplitude/Phase Mask applied to a Detailed Source, which can be helpful in debugging and verification. In this script, dialogs prompt the user for a file name where data is to be stored...

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Determining Scatter Importance Sampling

Scatter Direction Regions of Interest are an integral part of an efficient scatter calculation, as they serve to direct scattered rays only towards areas of interest. In generating scattered rays, FRED evaluates the solid angle subtended by the Scatter Direction Region of Interest and handles...

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Imaginary refractive index to absorption converter

The attached FRED script file will retrieve the imaginary refractive index value for a sampled material type, create corresponding wavelength and absorption coefficient pairs for that material, and set the absorption flag active.  In this implementation the conversion between imaginary refractive index and absorption coefficient...

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FRED Network Key Setup Guide

This Guide explains how to set up a FRED network key server, how to update the authorization codes on the key server’s USB dongle, and how to prepare the client computers to use the network key. [pdf-embedder url="https://photonengr.com/wp-content/uploads/2010/11/FREDNetworkKeySetupGuide.pdf"] ...

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