12 Replies Latest reply on Oct 1, 2009 6:07 PM by Jeffrey Smith

Smoothing objects which has been created from CTscan/MRI images

hani bakhshaei Sep 28, 2009 4:59 PM

Hi,

I have created some geometries(.stl) using CTscan data. I have to import them for CFD or Finite element analysis and surfaces should be very smooth. I have 2 questions:

1- How can I smooth the surfaces in Solidworks?

2- I use another software to creat geometries based on CT data. Is it possible that I import Ct data and make 3D objects directly in solidworks?

Thanks ,

Hani

Re: Smoothing objects which has been created from CTscan/MRI images

1-4EQZK9 Sep 28, 2009 10:56 PM (in response to hani bakhshaei)

hani,

Through the use of ScanTo3D which is part of SW Premium. Depending on the part type (organic or product design) you can use auto-surfacing or guided-extracted surface method respectively.

If you want to post the STL, or sample of it, I can show you.

Regards

Mark
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Re: Smoothing objects which has been created from CTscan/MRI images

Kevin De Smet Sep 29, 2009 2:53 AM (in response to hani bakhshaei)

I was always curious, what does raw CT/MRI data come as?
I know its geometrically based on voxels, but what file format does it have?

I too wonder if it can be brought into Solidworks straight away - or whether it has to be tesselated into an .STL - then ScanTo3D will surely do it, as Mark said.
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Re: Smoothing objects which has been created from CTscan/MRI images

hani bakhshaei Sep 29, 2009 6:24 PM (in response to hani bakhshaei)

Well as I said, my main problem for the time being is how to smooth the geometry that I have. I have made a 3D geometry based on CT scan data using "ITK-Snap" software. In their website you can find a set of MRI data. Ouput format of ITK-Snap is .stl file and I want to smooth the rough surfacesby SolidWorks.
Another idea is to do it using CATIA, but i could not open that stl file in CATIA.
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- Re: Smoothing objects which has been created from CTscan/MRI images
  
  Kevin De Smet Sep 30, 2009 2:08 AM (in response to hani bakhshaei)
  
  No way...you can't open something in CATIA without first buying some obscure module that costs you an arm and a leg...count me amazed
  
  Well, if it's an .STL, you can make use of smoothing groups. I think the free software Blender allows you to do that, it works by interpolating light across the vertices of polygons. That'll make it smooth - but be aware, this is only a visual effect! It's an illusion of light, and the actual underlying geometry will not become smooth to a CNC cutter, rapid prototyping machine or simulation software.
  
  You could also subdivide the mesh, which does make it smooth geometrically, however an .STL is triangles and smoothing algorithms perfer quads - which would be an insane amount of work. If you can find software that works on the Loop alogrithm you might be able to do something: http://en.wikipedia.org/wiki/Loop_subdivision_surface
  
  However, simulation software doesn't like polygonal data because it needs to tesselate itself, and it has a completely different algorithm.
  
  So, best of all, if you have ScanTo3D you can have Solidworks clean up your .STL and semi-automatically generate surfaces that allow you to make it very smooth. What does the scandata contain? Are you looking at a lot of work or is it like a single bone?
  
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  - Re: Smoothing objects which has been created from CTscan/MRI images
    
    Jeffrey Smith Sep 30, 2009 5:55 PM (in response to Kevin De Smet)
    
    I have a similar problem. I found a great source of anatomical models, but they are only in formats that I can't read into SolidWorks (.max, .obj, .lwo, .xsi, .fbx). I spoke to the company, and they converted the file I needed to .STL, but I don't have the ability to modify that model once it's been parsed into SolidWorks. Am I missing something?
    
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    - Re: Smoothing objects which has been created from CTscan/MRI images
      
      1-4EQZK9 Sep 30, 2009 7:08 PM (in response to Jeffrey Smith)
      
      Hani and Jeffrey,
      
      The attached images are from a hand that I exported via .obj from PoserPro and into SW ScanTo3D and made solid using the AutoSurfacing function.
      
      Regards
      
      Mark
      
      scanto3d-hand2.jpg 84.5 KB
      
      scanto3d-hand.jpg 45.8 KB
      
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      - Re: Smoothing objects which has been created from CTscan/MRI images
        
        Matt Lombard Sep 30, 2009 9:51 PM (in response to 1-4EQZK9)
        
        Yes, but that requires SolidWorks Premium, right? Do the people asking the question have Premium?
        
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      - Re: Smoothing objects which has been created from CTscan/MRI images
        
        Jeffrey Smith Oct 1, 2009 11:28 AM (in response to 1-4EQZK9)
        
        That looks like what I want to do. I have the .obj file (as well as other formats), but the ScanTo3D crashes SolidWorks every time I try to run the smoother.
        
        I do have SW Premium.
        
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        Re: Smoothing objects which has been created from CTscan/MRI images
        
        1-4EQZK9 Oct 1, 2009 5:44 PM (in response to Jeffrey Smith)
        
        Jeffrey,
        
        Sound like you may be hitting a memory limit; either simplify the mesh with the mesh prep wizard or get on SWx64.
        
        Regards
        
        Mark
        
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        Re: Smoothing objects which has been created from CTscan/MRI images
        
        Jeffrey Smith Oct 1, 2009 6:07 PM (in response to 1-4EQZK9)
        
        Mark,
        I'm already on X64. I think this might be a memory limit as well. Need to watch my performance while I'm trying to load this...
        
        Thx,
        Jeff.
        
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Re: Smoothing objects which has been created from CTscan/MRI images

hani bakhshaei Oct 1, 2009 3:57 PM (in response to hani bakhshaei)

Thank you very much Mark and Kevin,

Mark,mine is student kit and I do not think it has the ScanTo 3D. As you said it is in permiume version. But I checked the help of SW and it is exactly what I want. Is it possible that I send 2or 3 files and you have a look at them and see whether you can smooth their surfaces or not?

Thanks
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- Re: Smoothing objects which has been created from CTscan/MRI images
  
  1-4EQZK9 Oct 2, 2009 8:49 AM (in response to hani bakhshaei)
  
  Hani,
  
  check your add-in's - Is it listing ScanTo3D ? ScanTo3D should be included with the EDU version.
  
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