Re: 3D medical modelling

From: Panayiotis Diamantopoulos (
Date: Thu Mar 07 2002 - 17:52:13 EET

Dear Brian, List,

I agree with many of the points made by Bill Richards and Richard Bibb, and believe that there is a quite large number of software packages available that could potentially be used for medical modelling (either 3D or physical).

My research unit has been looking at the possible integration of medical imaging with CAD, FEA and RP for some years now, and most of the time we can reach our goals by combining the apropriate software packages.
I agree that new software tools could facilitate specific applications, but I think that these would basically target and assist medical staff who may not have the appropriate CAD skills. A CAD engineer user, I think, that can already achieve the specific requirements of most medical applications.

There is plenty of software tools available that can also provide, in a way, a choice of accuracy. For example, the processing of medical images to RP, which is now well-established, has been demonstrated to provide the necessary accuracy for preoperative planning and custom-made implants (which basically are the majority of current CAD/RP medical applications). The same file (STL format) can also be used in various CAD packages at least for visualisation purposes, if not for further modelling. However, any further CAD modelling is most of the time required for simulation packages, such as FEA, and it is therefore pre-accepted that this will be an approximation of the reality. Even though, the CAD models generated with available software packages (usually based on NURBS) are very good approximations. For example, a 3D model of a bone structure developed through Mimics, exported as IGES, and made a solid into Rhino, can be a very good model which in most cases is acceptable for medical simulation applications.

I think then, that the current immediate problem is not really the availability of software packages, but it is the availability of a common robust file format. For example, if IGES could work as it should, then this would solve many problems. In addition, most software packages do not provide all import/export facilities with the standard module, but usually there is an extra cost (often quite expensive). This may be right, but in practical terms it can often become a serious problem, especially for medical applications when a certain degree of research is always involved.

To conclude my long message, I believe that the main problem is not a lack of software facilities, but a lack of actual practical integration. If this could be resolved, there are many interesting medical applications. We could really speak about CAD-based or engineering-integrated surgery which I do not think that is very far away.

Best regards,


Panos Diamantopoulos, DPhil
Application & Development Manager
Bio-Medical Modelling Unit (BioModel)
School of Engineering
University of Sussex
Brighton BN1 9QT
Tel: +44 1273 877320
Fax: +44 1273 877341
  ----- Original Message -----
  From: Brian Caulfield
  To: Rapid Mailing List
  Sent: 06 March 2002 20:25
  Subject: 3D modelling

  Dear All,

  I find that using animation tools such as 3DMAX and other programs like Rhino are very benefical for both 3D computer models and making actual physical models. I use MAX to help smooth contours and increase clarity of NURBS curves that are exported for MIMICS.

  When I use these programs I am generally talking about Medical Models or very complex non-linear models which can't be dealt with by the usual methods i.e. CAD.

  Do you think that there should be a strong link with these types of programs and RP/Modelling and with such technolgy increasing at a dramatic rate ( We only have to look at animations now a days) it would be better to use that than try and design specific Medical Imaging tools.

  What do you all think.


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