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get a 3D model of an ankle into proE

daniella

New member
A same type of question was asked a few years ago on this form, the problem is i don't understand much of it. I'm a student and for my final year model I am comparing ankle implants, modelling an ankle, calculating stresses & strains etc, to design a hopefully new and improved implant. My main problem is, I don't know much about how all this works... I am assuming I definetly need an MRI or CT (?) scan, but how do i get it into proE? also i have been told that proE 5 now does FEA, so I wont need to model anything in ansys ?


If anyone could help me, it would be well appreciated!!


thanks
 
One way of getting an ankle scan into Pro/e is to take the DICOM data (Standardized format for MRI & CT scan data) and use a points to surface tool like Geomagic or Pro/e REX. Using one of these you can then create an IGS or STL that can be brought into Pro/e. I'd recommend an IGS as an STL is not as flexbile. With an IGES you can cut it with planes or surface "blobs" and remove chunks represented by the implant.

View attachment 4711

View attachment 4712

How are you going to do the FEA? Are you going to take into account the ligaments and tendons? Or are you simplifying to just do the bone loading?



Edited by: jsantangelo
 
Thank you very much, now I just need to find an MRI scan of someones ankle :)


About the FEA, I have no idea what and how I can do it yet. Preferably like to include tendons and ligaments, but I am not sure I am capable.


If there are ideas out there how to do this, I am all ears. I am still in the research stage, thus still a bit blind sided.
 
daniella said:
Thank you very much, now I just need to find an MRI scan of someones ankle :)


About the FEA, I have no idea what and how I can do it yet. Preferably like to include tendons and ligaments, but I am not sure I am capable.


If there are ideas out there how to do this, I am all ears. I am still in the research stage, thus still a bit blind sided.

Keep it simple. Use basic/simple assumptions. This will make your life much easier especially if this is your first stab at FEA. The ankle, like the knee, is a very complex mechanism.
 
I agree. Adding the complexity of soft tissues to the
problem would create a PhD thesis!

Look at the Mimics software for a method of getting 3D
models out of CT data.
 
That would be the best way, as I am pretty sure, I will not be able to to implicate all of that. But I am worried it will make it completely unrealistic...


I don't have mimics software, I'm trying to find a trial version, well my main issue is still finding a scan of an ankle.
 
The ankle is made up of different bonesbones, the tibia, fibula, talus
and calcaneus, which form three different joints, talocrural Joint, inferior tibiofibular joint and the subtalar joint. Its a hell of piece of engineering, and not one I would like to replicate.

I think you will have to start with a simplification, either a static assembly with assumptions for the interface, or a simplified mechanism. Reverse engineering the bones themselves is a big enough job in itself.


I can't offer much more in the way of help but would certainly be interested to see how you go on.

Sam
 
daniella said:
That would be the best way, as I am pretty sure, I will not be able to to implicate all of that. But I am worried it will make it completely unrealistic...


I don't have mimics software, I'm trying to find a trial version, well my main issue is still finding a scan of an ankle.

Assumptions and simplifying things are part of the engineering process. Better get used to it.
 
True, just feels like cheating.


See how it goes once i have found an mri ;)


thank you for your help, ill probably have many questions when i actually start.
 
Here are some free DICOM Segmentation packages incase you don't have the $15k US for Mimics.

3D Slicer - http://www.slicer.org/
SliceOmatic - http://www.tomovision.com/
3D DataDoctor - http://www.ablesw.com/3d-doctor/

The
basic idea is to go slice by slice of the DICOM data then paint or mark
the bone/anatomical item that is of interest. The 3D DataDoctor link
shows that concept in 3 pics. Each of the above software packages do
all that you just have to figure out what button to hit, kind of like
switching between SoildWorks and Pro/e. They do the same thing but use
different buttons. But there are tutorials and info on each software
package. The 3D Slicer may be your best bet as there are lots of
tutorials for that one and it's OpenSource.
 
It sounds like you are just needing an ankle bone, sorry if I over simplified that as I don't know the entire complexity of the ankle. From reading this, you aren't really interested in one single persons benefit from and ankle implant, rather, how well does different implants work. You also sound like you must be in a medical field or a senior class of some sort and this would be your senior project to be wanting to revolve all of this around the ankle bone. From that, I'll assume you have the ability to get a hold of an ankle bone in real life (even a scaled model will work as long as it is a true scale of an actual ankle bone). If you can do this, you might want to look into the possibility of your school/employer possessing a 3D Scanner. A 3D scanner will measure many, many, many points along the surface of what you are wanting to scan resulting in a point cloud cluster which can then be used to create an STL file or IGES depending on the machine. From this you can be certain you have a perfect model to start with. I had to do this for a job awhile back with a knee brace which is very complicated to measure whether you believe that or not due to the wild contours of the components to form to someones leg. It worked great for us, but like I said, it all depends on having an original and a 3D scanner. Some places might have one that they'll let you use for a fee, but I would imagine that fee would have to be considerably less than running an MRI machine, insurance doesn't cover school projects :p
 
I finally have managed to occure some ankle scans, but now have no idea what to do. as i dont have a medical background i can barely figure out what is on aof these cds.
 
Daniella,


As a result of this post, I've been playing around with the slicer.org software, and it's pretty neat. You're cd most likely has dicom data, in which you'll need to import it into the slicer software. Next, you'll need to segment the bone from the other materials. The slicer software can automatically translate the segment from the orignal slide to the adjacent slides, and as a result you'll be able to create a volume of the bone. Next, you export it out as an stl.


That's the rough cut anyways, for the detailed button clicks, you'll need to teach yourself that using the documentation like the rest of us. Good luck!


Jim
http://www.linkedin.com/in/shawengineering
 
jimshaw said:
That's the rough cut anyways, for the detailed button clicks, you'll need to teach yourself that using the documentation like the rest of us. Good luck!

I agree.

Jim - How's your shoulder model coming?
 
Slowly... the (lack of) documentation is pretty bad, and the workflow is really bad (as always withimmature open source). I've been able to complete the segmentation tutorial, and import a brain tumor, but now I'm going through the trial/error process of tweaking the segmentation parameters to get the proper volume out of my own slides... I imagine this step is going to take me a while...


Jim
http://www.linkedin.com/in/shawengineering
 

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