<p>This solution assumes the following </p>

<p>a-The scaling factor for the object is correct i.e real world dimensions .</p>

<p>b- There is a .STL file available . </p>

<p>c- <strong>This will take some 3ds max skill and time .</strong> </p>

<p><strong><em>Steps to be followed -</em></strong> </p>

<p>1- Take the .stl file into Autodesk 3ds max . </p>

<p>2- Now we are going to trace the exposed surface using a process called <strong><em>reptology</em></strong> . Here is link to get you started - <a href="https://www.youtube.com/watch?v=azkbuZloTqo" rel="nofollow noreferrer">https://www.youtube.com/watch?v=azkbuZloTqo</a> .</p>

<p>3- Once you are satisfied with recreating the mesh and sure it is as accurate as humanly possible , run the measure utility on the recreated part . </p>

<p>This is the link . <a href="https://knowledge.autodesk.com/support/3ds-max/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/3DSMax/files/GUID-12CDEA7A-042E-4CB3-9BF6-8191D3290CD8-htm.html" rel="nofollow noreferrer">https://knowledge.autodesk.com/support/3ds-max/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/3DSMax/files/GUID-12CDEA7A-042E-4CB3-9BF6-8191D3290CD8-htm.html</a> .</p>

<p>If there is a upper side and a lower side to the model then you should divide the surface area in half ( in this case it would be ).</p>

<p>3Ds max is very accurate if your part is designed properly .</p>

<p>4- This can be done directly on the .STL file if you can efficiently isolate your target area , lemme warn you this is not an easy task .STL files are notoriously difficult to edit. ( its much easier to redesign on top  ) </p>

<p>Try it should work out fine . </p>

<p>Please do not waste time processing .STL files on 3D-Slicer, Seg3D, ITK-Snap
they are mostly for file preparation i.e (.STL file generation ),viewing and study purposes only .</p>

CC BY-SA 4.0
2018-06-26T11:39:57.587Z
2018-06-26T11:39:57.587Z
Axel Fernandes
<p>I am using (micro)CT data and generating 3-D models using CTAn - a SkyScan piece of software: <a href="http://bruker-microct.com/products/downloads.htm" rel="nofollow noreferrer">Bruker - Control and reconstruction programs</a>.</p>

<p>Basically I am using simple thresholding to create 3-D model STL files.  </p>

<p>What I would like to do is get the number of voxels where the surface area of the two models touch.  </p>

<p>Imagine having a model that is a sphere with another model within it that is exposed on a portion of the sphere.  I want to know the surface area of that exposed portion.  </p>

<p>Does anybody have any advice?  I have been banging my head against tools like 3D-Slicer, Seg3D, ITK-Snap and so on and have not been able to find this capability.  </p>

<3d-models>
CT Segmentation Model Intersection
Daniel
# CT Segmentation Model Intersection

(Asked by: username_0 on 2017-02-06)

I am using (micro)CT data and generating 3-D models using CTAn - a SkyScan piece of software: [Bruker - Control and reconstruction programs](http://bruker-microct.com/products/downloads.htm).

Basically I am using simple thresholding to create 3-D model STL files.

What I would like to do is get the number of voxels where the surface area of the two models touch.

Imagine having a model that is a sphere with another model within it that is exposed on a portion of the sphere. I want to know the surface area of that exposed portion.

Does anybody have any advice? I have been banging my head against tools like 3D-Slicer, Seg3D, ITK-Snap and so on and have not been able to find this capability.

**Tags:** 3d-models

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## 1 answers

### Answer by username_1 on 2018-06-26. Score: 1

This solution assumes the following

a-The scaling factor for the object is correct i.e real world dimensions .

b- There is a .STL file available .

c- **This will take some 3ds max skill and time .**

***Steps to be followed -***

1- Take the .stl file into Autodesk 3ds max .

2- Now we are going to trace the exposed surface using a process called ***reptology*** . Here is link to get you started - <https://www.youtube.com/watch?v=azkbuZloTqo> .

3- Once you are satisfied with recreating the mesh and sure it is as accurate as humanly possible , run the measure utility on the recreated part .

This is the link . <https://knowledge.autodesk.com/support/3ds-max/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/3DSMax/files/GUID-12CDEA7A-042E-4CB3-9BF6-8191D3290CD8-htm.html> .

If there is a upper side and a lower side to the model then you should divide the surface area in half ( in this case it would be ).

3Ds max is very accurate if your part is designed properly .

4- This can be done directly on the .STL file if you can efficiently isolate your target area , lemme warn you this is not an easy task .STL files are notoriously difficult to edit. ( its much easier to redesign on top )

Try it should work out fine .

Please do not waste time processing .STL files on 3D-Slicer, Seg3D, ITK-Snap
they are mostly for file preparation i.e (.STL file generation ),viewing and study purposes only .


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