MATLAB: How to get coordinates values X, Y, Z from the Meshed file in matlab

to extract coordinates from meshed model

I have a meshed bone model(stl file). I have to extract data points (X,Y, Z coordinates) from the model which has 4000 nodes.

Can anyone suggest some idea to proceed?

Best Answer

Something like this

TR = stlread('tristltext.stl');
x = TR.Points(:,1);
y = TR.Points(:,2);
z = TR.Points(:,3);

Related Solutions

MATLAB: How could I create stl file based on the ellipsoid command

stlwrite only support triangles.

You can get the alphaShape of ellipsoid using the alphaShape function.

shp = alphaShape(tr.Points)

There is also the freeBoundary function.

[F,P] = freeBoundary(tr)
trNew = triangulation(F,P)
stlwrite(trNew, "freeboundary.stl")

MATLAB: How to convert a triangulation object into volume and create a BITMAP image

Below code is a good example for creating a STL file for 3D geometry, read the STL as traingulation object, save it as bitmap image and calculate the volume:

Script to create a STL file for 3D geometry. eg: cylinder

[X,Y,Z] = cylinder(r,100);
DT = delaunayTriangulation(X(:),Y(:),Z(:));
TR = triangulation(DT.ConnectivityList,DT.Points);
[F,P]=freeBoundary(TR);
TR = triangulation(F,P);
stlwrite(TR,'stl_test000.stl');

Method 1: may not be accurate for complicated shapes

%read the stl as a triangulation
gm = stlread('stl_test000.stl');
% use alphashape to create a bounding volume
shp=alphaShape(gm.Points);
plot(shp)
% If the plot does not look like the shape that you are expecting, change
% the critical radius for the alphashape
shp.Alpha = 5;
plot(shp); % this should plot the cylinder. the plot can be saved as a bitmap
% Get the volume value
shp.volume

Method 2: more accurate. Needs PDE Toolbox

pdem = createpde;
importGeometry(pdem,'stl_test000.stl');
% plot the geometry (3D)
pdegplot(pdem); % the plot can be saved as a bitmap
% mesh the geometry. For more accuracy, adjust the Hmax
msh = generateMesh(pdem,'Hmax',0.1);
% calculate the volume
msh.volume()

Best Answer

Related Solutions

MATLAB: How could I create stl file based on the ellipsoid command

MATLAB: How to convert a triangulation object into volume and create a BITMAP image

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