Getting - Matrix dimensions must agree, using surf

>> Paving

??? Error using ==> surface

Matrix dimensions must agree.

Error in ==> C:\MATLAB6p1\toolbox\matlab\graph3d\surf.m

On line 68 ==> hh = surface(varargin{:});

Error in ==> D:\Matlab\MATLAB6p1\work\Paving.m

On line 38 ==> surf(X,Y,Z)

Answer 1

[Walter Roberson]

When you call surf(X, Y, Z) in your very old release, the number rows in Z must match the number of rows in Y and the number of columns in Z must match the number of columns in X. However in your code, X, Y, Z are all vectors.

surf() can never be used to turn a set of scattered points into a surface.

[Walter Roberson]

That version of MATLAB is 20 years old, and I no longer recall what you would have to do in order to create a surface from scattered points for it. Something similar to using qhull() to create some kind of triangulation and creating a mesh from that.

The recommended approach has changed at least twice in the 20 years since your release.

[William Blanch]

Thank You Mr. Roberson for your help. It works for the attached code (an example).

What I am doing is using Moasure One to get 3D data for a plot of land. It outputs to me the x,y,z coordinates in an Excel file and I want to get an stl file from the surface plot and open the flie in Solidworks as a part and use it as the base of an assembly that adds the design of a house that is going to be built on the plot of land.

Billy

[Walter Roberson]

That example has each of x1 and so on be a column vector. When you [] five of those together you get an Nx5 array. Your X, Y, Z are then 2d arrays.

Your earlier code is using single columns for each of the x y z, and surf() cannot work with vectors.

[Walter Roberson]

If what you are dealing with is an outline of an area then if you have the Image Processing Toolbox then

https://www.mathworks.com/help/images/ref/poly2mask.html

[Walter Roberson]

Your original data appears to be an ordered list of points in 3 space.

It is not obvious what it means to draw a surface plot of it. I suspect, though, that what you want would be something similar to taking the X Y Z vertices and duplicating them with a slightly larger Z, and then drawing connecting lines between the original X Y Z and the X Y (Z+delta) . You could do that with patch() with the Faces and Vertices inputs

XYZ2 = [X, Y, Z; X, Y, Z+delta];
faces(1,:) = 1:length(X);
faces(2,:) = fliplr(length(X)+1:2*length(X));  %opposite side, should go backwards

then create a series of additional rows that individually define rectangles in a consistent orientation, with the unused entries in each row being set to NaN.

[William Blanch]

Thank You, but what I need is an .stl file so that I can create a part of it in Solidworks. Can you get an .stl file from a patch?

[Walter Roberson]

https://www.mathworks.com/matlabcentral/fileexchange?q=patch2stl