Tools - BSDF Data Fitting - Binomial/Polynomial

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Binomial/Polynomial Data Fitting

Page Contents

Description

This utility fits data from a properly formatted file to isotropic Diffuse Binomial/Polynomial scatter models shown below and leverages the file format and interpolation scheme of the Tabulated BSDF scatter model prior to fitting the data. An option exists on the dialog for opening up a preview plot of the raw data as well as the fitted model for confirmation of the fit before adding the model to the document. Remember that due to the nature of the polynomial functions, it is particularly important to plot the resulting model after it has been added to the tree since the preview plot only displays fitted data at the same angles as the input file. At other angles, the fitted polynomial/binomial function may exhibit behavior that is not physical.

Binomial

Polynomial

Navigation

This feature can be accessed by selecting Tools > BSDF Data Fitting > Binomial/Polynomial Data Fitting from the menu.

Controls

Control	Inputs / Description	Defaults
Path	User file name
Browse	Open file dialog for file selection. The data file is formatted in the same way as the Tabulated BSDF scatter model.
Function
Binomial	Binomial (plane symmetric)	Unselected
Polynomial	General polynomial	Unselected
Options
Generate out-of-plane data	Generate out-of-plane data from in-plane data.	Unchecked
Write data	Write data to file.	Unchecked
Ignore above maximum	Ignore data above given value.	Unchecked
Ignore above minimum	Ignore data below given value.	Unchecked
Optimize Lorentizian d	Find the optimum value for Lorentzian d parameter	Unchecked
Type
Diffuse	Select only the diffuse term.	Unselected
Lorentzian	Select only the polynomial term.	Unselected
d	Lorentzian factor.	10000
Both	Select both Diffuse and Lorentzian terms.	Selected
Fit
Fit to a specific function	Use only the specific n m l l’ parameters provided.	Selected
Regression fit	Fit to all combinations of n m l l’.	Unselected
Interp/sample	When toggled, additional data points are added to the input data set by interpolation before fitting is performed. The value is interpreted as a multiplier on the number of data points input from the file. For example, if a multiplier of 2 is used, there will be 2x the number of input data points used for fitting with half of them coming from interpolation.	Unchecked
Parameters
n m l l’	Summation index parameters. When the "Regression fit" option is selected, the user enters the minimum and maximum parameter value ranges that should be attempted to be fit. If the "Fit to a specific function" option is selected, then the summation index parameters are explicitly entered.	0, 0, 0, 0
Read Data Samples
Info	Number of samples read for fitting.
Fit Error Summary
Table	Tabulates specific/regression results.

Create Model	Create model and add to FRED document.
Close	Close dialog box.
Perform Fit	Fit data using input parameters. Keeps dialog box open and displays results.
Help	Access this Help page.