No announcement yet.

Geometric models

This topic is closed.
  • Filter
  • Time
  • Show
Clear All
new posts

  • Geometric models

    Dear All

    A couple of weeks ago I asked a question about 3D model creation.
    Basically, I wanted to know if there were people out there creating
    models from anatomic data and if so how were they doing it and would
    they be prepared to share their models.

    A big thanks to those people who did reply.

    I recieved a number of messages asking me to send them a summary of
    my replies - the question itself turned out to be very common, but
    the answer less so. The following are the responses I recieved. I
    would welcome any further replies.



    >With regard to your questions regarding the VHP, I followed the
    discussion last year but found most people unwilling to divulge their
    hard work, especially those that had developed models for use in
    CAD/FE. It does seem silly not sharing this info as it is only a
    small aspect of work and could be of great use to a large number of
    people. I feel sure that somebody must have published this as part of
    their thesis which is probably very difficult to track down. The
    commercial software seems a bit expensive.
    I'm afraid that at this moment I do not have any models to share,
    what are you looking for in particular?? We have developed models of
    the knee, spine and ankle by a technique involving physical
    measurement using a co-ordinate measuring machine and IGES files.. I
    am currently working on a technique to develop models from the VHP
    dtaa, however this work is not complete yet. The method I intend to
    build involves using the CT data and putting it into IGES format.
    Dont know to what extent all of this will be done automatically, it
    may require some input and manipulation.
    Chris Connor, email:
    School of Science & Technology University of Teesside

    >I am sending you a copy of a technical report that describes the
    spatial geometry of the human pelvis. I conducted a study with Clyde
    Snow and Joe Young several years ago in which we measured 165
    skeletal pelves from the Cleveland Museum of Natural History. The
    results were used to develop small female, average male and large
    male pelves for the US Department of Transportation. The
    three-dimensional data describe the location of approximately 122
    points on the pelvis. I believe that you can use this information
    in your model quite easily. If you have any questions after receiving
    the report, please feel free to contact me.
    Mac Reynolds, Ph.D. , email:
    Ergonomics Research Laboratory Michigan State University

    >In reply to your request for numerical data of the pelvis and femur,
    I can tell you that I am working on a mathematical model of the
    pelvis/low back. The aim is to calculate muscle forces, forces in
    ligaments and joint reaction forces in several postures and under
    several loads. (So it will NOT be a FEM of bony structures). For this
    model, I need lots of geometrical data, so we made a set of
    MRI-scans of one subject. The contour of all structures that are
    important for me was determined by hand: drawing contours with the
    computer mouse. The final result is a data set of contours of -among
    others- the pelvis and the femur. The distance between the slices is
    5.5 mm, the accuracy of the contours is determined by the skill of
    the person that draws the contours, I can't give a quantitative
    measure for that. These contoures are stored in a numerical format
    in my computer.
    Gilbert A. Hoek van Dijke, email:
    Department of Biomedical Physics and Technology Erasmus University

    >In recreating the geometry of soft tissue knee structures from
    magnetic resonance images, we have been using three pieces of
    software, PV Wave, Nuage, and GeomVIEW. I would attempt to give you
    more detail, but I am learning myself. I am currently taking a
    class in AutoCAD in hopes of replacing or aiding the programs which
    we use now.
    Tony Francisco, email:
    Duke University Sports Medicine

    >Some years ago I made efforts to analytically represent the geometry
    (asphericity) of the human femoral head. My results were published in
    two South African Journals ( my post-doc was in this country):
    -Mizrahi J: The human femoral head as a tilted solid of revolution.
    South African Journal of Science, 73(9), 385-386, 1977. -Mizrahi J:
    An axi-symmetrical representation of the human femoral head. The
    South African Mechanical Engineer, 28, 206-209, 1978.
    Prof. Joseph Mizrahi , D.Sc., email:
    Dept. of Biomedical Eng. Technion,
    Israel Institute of Technology

    >You should take a look at or They have NURBS models of what you are
    looking for. They've built them after digitizing real bones.
    Richard Bastien email :
    R&D department, Decathlon

    Original Message

    I am about to start the process of creating a basic 3D model of the
    pelvis and proximal femur, for use in both FE and CAD analysis.

    With the arrival of the Visible Human data set and the availablilty of
    this data for all researchers, I know a number of centers are spending
    time and resources creating geometries from the images. There are
    also comercial companies using this data, but the models they are
    creating are 3D models in a non-mathematical format.

    I searched the Biomch-l archives and came across a discussion from
    last year regarding sharing of model geometry. There was however no
    conclusion to this discussion. For each individual researcher to
    undertake the same process of model creation from the same data would
    surely be futile. Or pehaps I am simply trying tojustify my lazyness.
    I could create the model myself, but as this is simply a tool for
    further analysis, I was hoping the basic geometry in a numberical
    format was available from some other source.

    My question to the biomch-l community is, do any of you have a
    goemetric model that you would be prepared to share with another
    researcher? Again this should not only apply to my case, but in
    general. Alternatively, could you tell me how you approached the
    problem of creating the goemetry from either the scanned images, the
    CT or the MRI images.

    Dr Rhona Phelps Industrial Research Ltd
    Research Scientist P.O.Box 2225
    Engineering Dynamics Auckland
    Biomechanics Group New Zealand

    Tel: +64 9 3034116
    Fax: +64 9 3070618