# FRED Knowledge Base

### Rectangular Lenslet Arrays

Lenslet arrays are used in a variety of applications that include beam homogenization.  This knowledge base article demonstrates the setup of an imaging lenslet array for creating uniform incoherent illumination on a detector.  The input beam has a gaussian profile with half width equal to...

### Cylindrical Lens Creator

FRED does not currently include a built-in cylindrical lens creator. Cylindrical lenses must be entered either manually surface by surface or by adding a catalog cylindrical lens and adjusting it accordingly. This knowledge base article includes a script that generates a cylindrical lens based on...

### Truncated Cone Builder

This knowledge base article demonstrates a script that will create a truncated cone subassembly consisting of two end planes and a tapered cylinder.  The cone is specified by the two end surface radii and the axial height of the truncated cone.  In this implementation r1...

### Positions Spot Diagram Calculation

As of version 10.41 there is no script command equivalent to the positions spot diagram analysis available in the GUI.  This knowledge base article details a script utility which manually performs the equivalent positions spot diagram analysis in the scripting language. Scripted Positions Spot Diagram PDF Download...

### Best Geometric Focus

The best geometric focus calculation can be made from the GUI ( Menu > Analysis > Best Geometric Focus ) and from the scripting language using the BestFocus subroutine. Performing this analysis using the scripting language can be quite useful because the calculation and any...

### Gaussian Beam Calculator for Creating Coherent Sources

Coherent sources are represented in FRED using a superposition of Gaussian beamlets. The ray grid spacing of the source is used to determine the waist and divergence of the beamlets. To properly model coherent propagation properties, the beamlets must remain Gaussian and perform best when...

### Calculating E-field components in script

This knowledge base article demonstrates a script utility which calculates the Re{} and Im{} components of the E field along the s, p, x and y directions for each ray in the ray buffer.  In the GUI this information is printed to the output window...

### Draw NURB Curve Control Points

This knowledge base article demonstrates a simple utility that can be used to draw a sphere at the position of each control point in a NURB curve.  This can be useful for visualization purposes when constructing geometry made from this curve type.  The designated NURB...

### Birefringent Material Temperature Modification

Currently, FRED does not support “global” temperature settings and evaluations of temperature sensitivity are generally undertaken using the scripting language.  This knowledge base article demonstrates a script which implements a change in refractive index with temperature for a birefringent material. The attached example file contains two...

### Surface Height Profiler

This knowledge base article describes a utility which calculates the surface sag for each pixel in a 2D grid placed over the entity’s outer trimming volume. Pixels outside of the trimming volume bounds are populated with “hole” values while pixels inside of the trimming volume...