# Plot a surface with cross-section matrix

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Mateo Landazuri Pachano on 2 Sep 2020
Edited: Bruno Luong on 3 Sep 2020
Good day,
I am looking on how to create a 3D surface directly on matlab (to be converted to igs and exported to Fluent). Currently I have a portion of a missile-like shape and I have the crossections stored in a matrix. The matrix size for the angular values is 576x640, meaning there are 576 cross-sections and 640 points per cross-section. The radial values are stored in a matrix of equal size. The distance vector, or the one that dictates how far is one crossection from the other is of size 1x576. (one value per cross-section). I cannot share the code due to its lenght but hopefully my issue could be explained properly.
I currently need to make a surface out of these matrices, preferably a surface that can later be generated on Ansys or can be exported to Solidworks. Help is much appreciated.

So, do you have 576 values for z axis and for each one 640 pairs of x and y? right ?
Mateo Landazuri Pachano on 2 Sep 2020
Sorry, I do not know how to address you directly, but yes, I got 640 points for every crossection, and I got 576 crossections, also I got a z vector with 576. The way I have ordered the data is by having one matrix for angular values, and another for radial values. Each row of these matrices is one crossection, and each row has 640 columns, making both matrices 576x640. And then I have the z vector as 1x576, which I believe should be transposed...

Bruno Luong on 2 Sep 2020
Edited: Bruno Luong on 3 Sep 2020
theta = your_angle
z = your_z
% wrap around to close the azimuthal patch
theta = theta(:,[1:end 1]);
r = r(:,[1:end 1]);
x = r.*cos(theta);
y = r.*sin(theta);
z = repmat(z(:),1,size(x,2));
surf(x,y,z)

#### 1 Comment

The coordinates are not polar.