Ouputting data from a function to an array

Hi there,

I'm trying to output data from an sfit function to an array, so that I can use the surfnorm command. Basically I am receiving position data from Imaris, a 3-D visualization software and performing a surface fit. I am tasked with generating surface normals to the resulting surface (and I intend to use the surfnorm command). However, to create these normals, I need the xyz coordinates (in a particular range) from the resulting surface fit. How does one sequester the xyz coordinates for a surface fit (I'm using the thin plate spline interpolation)? Note--I already have turned the plotted function in the createfit function into a workspace variable called fitresult. However, whenever I open the variable in my command line, I receive the following answer.

 Thin-plate spline interpolant:
       fitresult(x,y) = thin-plate spline computed from p
       where x is normalized by mean 3760 and std 185.2
       and where y is normalized by mean 2812 and std 188.8
     Coefficients:
       p = coefficient structure

Thanks!

Cheers, Harsh

Answer 1

[dpb]

... the xyz coordinates (in a particular range) from the resulting surface fit

You had to have the coordinates to do the fitting; use those. If you need to select a subset within the total, use logical addressing. Perhaps giving snippet of the fitting code to show variables and more specifically where you're stuck???

[Harsh Patolia]

Hey dpb, many many many thanks for your swift reply!

Right now I'm just working off of the command line (I haven't wrote script yet to streamline the processing)--I'm fairly new to MATLAB programming. I am creating 3 workspace variables--x,y, and z. These are the imported coordinates from imaris. I then run the curve fitting toolbox to perform a surface fit. I just found out how to evaluate the surface fit function for all of my x and y values to output zfit values. However, now I'm stuck with the surfnorm command. Once I have my fitted surface coordinates, how can I generate the normals? I don't think I'm getting the syntax that MATLAB wants...

Once again, I really appreciate your help

[Harsh Patolia]

this is effectively what I'm attempting to generate:

[Harsh Patolia]

http://www.mathworks.com/help/examples/graphics/PlotSurfaceNormalsExample_01.png