How do you rescaling an STL surface in Matlab?

I have this code, but i don't managed to scale down the surface.

How do i do it?

Thank you

fv = stlread ( 'Femur_Head.stl' );

patch(fv,'FaceColor',       [0.8 0.8 1.0], ...
         'EdgeColor',       'none',        ...
         'FaceLighting',    'gouraud',     ...
         'AmbientStrength', 0.15);

% Add a camera light, and tone down the specular highlighting
camlight('headlight');
material('dull');

axis([-50 50 -50 50 0 80]);
 
view([-135 35]);
 
title('Femur Head');
 
xlabel('X');ylabel('Y');zlabel('Z');
 
% Fix the axes scaling, and set a nice view angle
 
axis('image');
view([-135 35]);
 
hold on

Answer 1

[Vaibhav]

Hi Alice,

I understand that you would like to scale down the STL surface.

The following steps outline an approach that can be taken:

• Retrieve vertices from the triangulation object:

vertices = fv.Points;

• Determine the scale factor for each dimension (adjust as needed):

scaleFactor = 0.5;  % Example: Decreases size by 50%

• Scale the vertices:

scaledVertices = vertices * scaleFactor;

• Plot the scaled STL:

trisurf(fv.ConnectivityList, scaledVertices(:, 1), scaledVertices(:, 2), scaledVertices(:, 3), 'FaceColor', [0.8 0.8 1.0], 'EdgeColor', 'none', 'FaceLighting', 'gouraud', 'AmbientStrength', 0.15);

The below code snippet demonstrates the scaling of the STL surface using "Torus.stl":

% Load STL file
fv = stlread('Torus.stl');

% Get the vertices from the triangulation object
vertices = fv.Points;

% Scale factor for each dimension (adjust as needed)
scaleFactor = 1.5;  % Example: increase size by 50%

% Scale vertices
scaledVertices = vertices * scaleFactor;

% Plot the scaled STL
figure;
trisurf(fv.ConnectivityList, scaledVertices(:, 1), scaledVertices(:, 2), scaledVertices(:, 3), ...
    'FaceColor', [0.8 0.8 1.0], 'EdgeColor', 'none', 'FaceLighting', 'gouraud', 'AmbientStrength', 0.15);

% Add lighting, adjust material properties, and set axis labels
camlight('headlight');
material('dull');
xlabel('X'); ylabel('Y'); zlabel('Z');

% Fix the axes scaling and set a nice view angle
axis('image');
view([-135 35]);

title('Scaled STL Surface');

Refer the below MathWorks documentations to know more about "stlread" and “trisurf”:

https://www.mathworks.com/help/matlab/ref/stlread.html?s_tid=doc_ta

https://www.mathworks.com/help/matlab/ref/trisurf.html

Hope this helps!