Save 3d surface plot as u3d or .ply file

Hello, I am having trouble in saving my matlab interactive 3d plot as u3d or .ply file.

I am unable to understand the file exchange: https://www.mathworks.com/matlabcentral/fileexchange/25383-matlab-mesh-to-pdf-with-3d-interactive-object.

Any help wor alternative would be greatly appreciated.

Below is my sample code.

%% Plotting the curve to be reflected
clear all
close all
clc
% Constants 
I0 = 1;                     % Initial X-ray beam intensity
rCu = 405;                  % radius of copper wire, um
rPMMA = 25;                 % radius of the PMMA, um
lamda = 7.1255e-5;          % x-ray wavelength, um, (17400 eV)
k = 2*pi/lamda;             % wavenumber, um^-1
beta_Cu   = 2.5914E-07;     % https://henke.lbl.gov/optical_constants/
beta_PMMA = 5.0314E-10;     % https://henke.lbl.gov/optical_constants/
%Xray

 mu_Cu     = 0.076E-4;
 mu_PMMA   = 4.165E-4
%% Computing intensity versus x-position 
%I(x)= I0*exp(−(µCu*LCu(x)+µPMMA*LPMMA(x))]
%Assume wire long axis is along z-axis, with center at x=0. 
%Assume x-rays travel in y direction.
rT=rCu+rPMMA;           % Total radius of the copper wire ,um
x=(-2:.04:1.98)*rT;        %x values (um) (range = +-2*rT)  
t_Cu=2*sqrt(max(rCu^2-x.^2,0));
t_total=2*sqrt(max(rT^2-x.^2,0));
t_PMMA=t_total-t_Cu;
It=exp(-mu_Cu*t_Cu-mu_PMMA*t_PMMA);
Iab = 1-It;

%% Guass
xstart=-2;
xstop=2;
xpoints=100;
xinc=(xstop-xstart)/(xpoints-1);
ystart=-2;
ystop=2;
ypoints=100;
yinc=(xstop-xstart)/(xpoints-1);
for ii=1:xpoints
    x(ii)=xstart+xinc*(ii-1);
    for jj=1:ypoints
        y(jj)=ystart+yinc*(jj-1);
        z=x(ii)*x(ii)+y(jj)*y(jj);
        Is(ii,jj)=exp(-z);
    end
end
% figure(2)
% plot(Is)
%% Detector intensity
M=It.*Is;
figure(3)
% subplot(211)
Z=log(M);
M=mesh(M)
title('Transmission plot','FontSize',13)
% xlabel('$x (\mumm)$','interpreter','latex')  
ylabel('$length (\mu m)$','interpreter','latex') 
zlabel('$Detector Intensity$ (arb.)','interpreter','latex') 
view([-4 12])
% Create textbox   
% Create textbox
annotation('textbox',...
    [0.733097718253965 0.811081794195249 0.0877356150793676 0.0360912174896386],...
    'String','Wire radius = 430 \mum',...
    'FontWeight','bold',...
    'FitBoxToText','off',...
    'BackgroundColor',[1 0 0]);
% Create textbox
annotation('textbox',...
    [0.730363343253966 0.767810026385223 0.108699156746034 0.0300226159065249],...
    'String','Coating thickness = 80 \mum',...
    'FontWeight','bold',...
    'FitBoxToText','off',...
    'BackgroundColor',[1 0 0]);
% VMRL export
%%
%% Absorption
Iabs=Iab.*Is;

Answer 1

[Deep]

To save a 3D surface plot as a .PLY file from your given "Surface" object "M", you can use the "pcwrite" function (https://www.mathworks.com/help/vision/ref/pcwrite.html) as shown below:

% Create a Nx3 matrix for N points
[XGrid, YGrid] = meshgrid(M.XData, M.YData);
xyzPoints = [XGrid(:), YGrid(:), M.ZData(:)];

% Create a point cloud object and save as .PLY
p = pointCloud(xyzPoints);
pcwrite(p, 'object3d.ply');

For saving your plot as a U3D file, the File Exchange link you mentioned converts the mesh data to an IDTF format, which is then transformed into a U3D file using third-party software. The face data required for this conversion is available in the properties of the "Surface" object "M". You can refer to the MATLAB documentation for more details: https://www.mathworks.com/help/matlab/ref/matlab.graphics.chart.primitive.surface-properties.html#buch_5e_sep_shared-FaceNormals.

For practical guidance, check the "demo_mesh2pdf.m" file included in the File Exchange link that you mentioned.