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Question about STL file

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Ano on 4 Dec 2018
Commented: Cris LaPierre on 18 Oct 2019
I have an STL file which contains the facets and vertices. My concern is about the way the facets are saved because I have noticed that the facets don't seem to have any common nodes with each other which is not obvious for me, so it would be very much appreciated if anyone can tell if this is normal or I am having some problem in my file!
Note: I have attached a screenshot of the STL file
Thank you and best regards!facets_stl.png


KSSV on 4 Dec 2018
Attach your file.....the faces/ triangles should be sharing nodes.
Ano on 4 Dec 2018
Thank you for you reply.
yes I agree that they should by they are not sharing nodes and the model seems to be correct!
Any ideas?!
Note: Please find attached the STL file and the facets and the nodes .
Thank you and best regards!

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Accepted Answer

Cris LaPierre
Cris LaPierre on 5 Dec 2018
Edited: Cris LaPierre on 5 Dec 2018
How are you reading the file into MATLAB? If I follow the example on the stlread documentation, I can import and plot the mesh.
data = stlread('femur.stl');
The interesting thing is the numbers from the various files are different.
  • stlread imports 33332x3 points and 66670x3 ConnectivityList
  • Your screenshot shows the values similar to what I see in ConnectivityList, but 178726x3 of them.
  • fv contains 66674x3 faces and 200022x3 vertices. How were faces and vertices created?


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Cris LaPierre
Cris LaPierre on 5 Dec 2018
Also, I suspect you are using a file exchange function, while I am using the function that comes with MATLAB. Please run the command
which stlread
I get 'C:\Program Files\MATLAB\R2018b\toolbox\matlab\polyfun\stlread.m'
Poornima Jayamani
Poornima Jayamani on 15 Oct 2019
Hi, Cris your suggestions worked well in my case. i am trying to calculate the volume of a triangular meshed left atrium using divergence theorem. However, when i try to iterate through 1 to number of triangles , the loop picking the same point as a first and third point after 16th iteration . i am not sure what could be wrong with my code.
Cris LaPierre
Cris LaPierre on 18 Oct 2019
Hard to say without seeing your file, but it sounds like you might need to clean up your stl file first. How was it generated?
Consider checking to see if the file is 3D printable. Also consider running it through an stl repair routine (many available online) just in case.

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