SigFit is an optical surface pre & post processor for NASTRAN™, ANSYS™, and COSMOS™ with a broad range of capabilities and easy user interface. Supported operating systems include Microsoft® Windows® 95/98/NT/2000/XP.

Polynomial Fitting
SigFit can fit a host of polynomial types to a wide array of input formats. Available polynomial types include standard and fringe Zernike polynomials, aspheric polynomials, X-Y polynomials, and best fit radius-of-curvature. After fitting is performed the residual peak-to-valley and RMS surface predictions are computed as shown in the table below. Plot files of residual surface deformations are provided in nodal formats for MSC/PATRAN™, FEMAP™, and ANSYS™.

Multiple Input Formats
Surface deformations may be described by finite element results, nodal files, interferogram hit-maps, or polynomial coefficients. Supported finite element codes are NASTRAN™, ANSYS™, and COSMOS™.

Multiple Output Formats
SigFit provides results in output tables for viewing and printing, nodal files for graphical plotting, and files for import to CODEV®, ZEMAX™, and OSLO™. Result files written for import to optical analysis codes include both files for rigid body motions and files for elastic deformations. The result files describing elastic deformation of optical surfaces may optionally be formatted as Zernike coefficients or array data. All output files are ASCII files which may be transferred to any machine platform.

Interpolation
SigFit can interpolate surface displacements from an interferogram to a finite element model, from a finite element model to an interferogram, or from one finite element mesh to another. This feature is often used to export analysis data to compare with interferometric test data. In addition, the importation of test data into SigFit is often used to perform adaptive control simulation with the actual measured figure of a mirror. (more...)

Adaptive Control Simulation
Adaptive control can be simulated for unwanted disturbances defined by finite element results, Zernike coefficients, or interferogram input. Polynomial fitting tables and plot files are provided for the uncorrected and corrected surface. (more...)

Dynamic Response
Modal techniques are used to calculate the transient, harmonic, or random response of surfaces using natural frequency analysis results. SigFit allows the user to define the dynamic loads and modal damping to compute the dynamic response of surface motions, polynomial coefficients, and residual surface error. (more....)

Design Optimization Support (MSC/NASTRAN™ Only)
Design optimization equations can be written in MSC/NASTRAN™ format for use in SOL 200 analyses. Equations can be written for Zernike polynomial coefficients, residual surface RMS, and residual P-V surface error. (more...)

Thermo-Optic/Stress-Optic/Stress-Birefringence Effects (NASTRAN™ and ANSYS™ Only)
Optical path difference (OPD) maps for import to optical analysis codes can be generated for transmissive optics from thermal or stress results. Additionally, phase maps can be generated for stress-birefringence calculations. (more...)

Two user interfaces, graphical and command line, are standard with SigFit.

Graphical User Interface
A Windows™ style program allows creation of input files in a graphical user interface. Input files may be imported, modified and saved to a new file. Execution then requires a single command line call referencing the input file. (more...)

Command Line User Interface
The original command line interface requires the user to answer prompts in the command window environment. We have preserved this interface to allow the user to batch many runs in series by using a .bat file.

SigFit is leased on an annual basis and requires acceptance of a lease agreement. (more...)