How to create an intermediate surface model from 2 Excel files with x, y and z cordinates where the number of rows in the matrices is different?

I have two surface models represented by coordinates x, y, and z in excel files, which correspond to the endpoints of a cardiac cycle.

However, these models do not have the same number of rows in their matrices. I need to create an intermediate surface model that the output takes the form of a surface mesh and a stl file.

The eode that I'm using is:

% Load data from Excel files for Model 1 and Model 2
[nome,caminho]=uigetfile(".xlsx","Ficheiro");
data_model1=fullfile(caminho,nome);
[nome,caminho]=uigetfile(".xlsx","Ficheiro");
data_model2=fullfile(caminho,nome);
% Extract x, y, and z coordinates from each data set
model1_x = data_model1(:, 1);
model1_y = data_model1(:, 2);
model1_z = data_model1(:, 3);
model2_x = data_model2(:, 1);
model2_y = data_model2(:, 2);
model2_z = data_model2(:, 3);
% Interpolate data to have the same number of data points
num_points = max(numel(model1_x), numel(model2_x));
model1_x_interp = interp1(linspace(0, 1, numel(model1_x)), model1_x, linspace(0, 1, num_points));
model1_y_interp = interp1(linspace(0, 1, numel(model1_y)), model1_y, linspace(0, 1, num_points));
model1_z_interp = interp1(linspace(0, 1, numel(model1_z)), model1_z, linspace(0, 1, num_points));
model2_x_interp = interp1(linspace(0, 1, numel(model2_x)), model2_x, linspace(0, 1, num_points));
model2_y_interp = interp1(linspace(0, 1, numel(model2_y)), model2_y, linspace(0, 1, num_points));
model2_z_interp = interp1(linspace(0, 1, numel(model2_z)), model2_z, linspace(0, 1, num_points));
% Create the intermediate model's data points using barycentric interpolation
intermediate_x = (model1_x_interp + model2_x_interp) / 2;
intermediate_y = (model1_y_interp + model2_y_interp) / 2;
intermediate_z = (model1_z_interp + model2_z_interp) / 2;
% Triangulate the intermediate model's data points to create a surface mesh
DT = delaunayTriangulation(intermediate_x(:), intermediate_y(:), intermediate_z(:));
% Save the intermediate model's surface mesh to an STL file
stlwrite('intermediate_model.stl', DT.ConnectivityList, DT.Points);
% Plot the surface mesh
figure;
trisurf(DT.ConnectivityList, DT.Points(:, 1), DT.Points(:, 2), DT.Points(:, 3));
title('Surface Mesh of Intermediate Model');
xlabel('X');
ylabel('Y');
zlabel('Z');

However, an error appears:

">> Matlab_medio

Error using interp1
Wrong number of input arguments.
Error in Matlab_medio (line 20)
model1_x_interp = interp1(linspace(0, 1, numel(model1_x)), model1_x, linspace(0, 1, num_points));"

Can you help me?

>>

[C B]

Can i know where have you read xls files?

i think you need to add readmatrix .

% Load data from Excel files for Model 1 and Model 2
[nome,caminho]=uigetfile(".xlsx","Ficheiro");
file_model1=fullfile(caminho,nome);
[nome,caminho]=uigetfile(".xlsx","Ficheiro");
file_model2=fullfile(caminho,nome);

data_model1 = readmatrix(file_model1);  % Read data from Model 1 file
data_model2 = readmatrix(file_model2);  % Read data from Model 2 file

% Extract x, y, and z coordinates from each data set
model1_x = data_model1(:, 1);
model1_y = data_model1(:, 2);
model1_z = data_model1(:, 3);
model2_x = data_model2(:, 1);
model2_y = data_model2(:, 2);
model2_z = data_model2(:, 3);

Answer 1

[Voss]

data_model1 and data_model2 are character vectors containing the names of the files, not the contents of the files.

Therefore model1_x = data_model1(:, 1) contains the first character of the file name stored in data_model1, and model1_y is the second character, etc.

For example:

nome = 'some_file.xlsx';
caminho = 'C:\whatever';
data_model1=fullfile(caminho,nome);

model1_x = data_model1(:, 1)

model1_x = 'C'

model1_y = data_model1(:, 2)

model1_y = ':'

model1_z = data_model1(:, 3)

model1_z = '\'

So then when you pass model1_x to interp1, it gets confused because model1_x is a character where interp1 was expecting numeric data.

num_points = 10; % whatever
model1_x_interp = interp1(linspace(0, 1, numel(model1_x)), model1_x, linspace(0, 1, num_points));

Error using interp1
Wrong number of input arguments.

To fix this, you need to read the data from the files, for instance using readmatrix:

[nome,caminho] = uigetfile(".xlsx","Ficheiro");
file_name1 = fullfile(caminho,nome);
data_model1 = readmatrix(file_name1);

[nome,caminho] = uigetfile(".xlsx","Ficheiro");
file_name2 = fullfile(caminho,nome);
data_model2 = readmatrix(file_name2);

% Extract x, y, and z coordinates from each data set
model1_x = data_model1(:, 1);
model1_y = data_model1(:, 2);
% etc.