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  • Responses to Retroreflective Marker Information Request

    I'd like to thank everyone for the large number of great suggestions I
    Here's the promised summary:

    Original Message-

    I'll need to obtain many more small (about 8-10mm) retroreflective
    markers soon, and with the prices vendors charge for them I'd like to
    look into finding alternative suppliers or making my own. Please let me
    know if you can help me with any of the following questions:
    -Suppliers of pre-made markers other than Vicon and B & L Engineering.
    Have you worked with a company that was preferable for some reason?
    -Suppliers for small diameter (8-10mm) spheres. Any kind of rigid
    plastic or even aluminum should be fine, but I don't think that we can
    drill and tap holes in spheres that small of anything harder.
    -Suppliers of high-quality retroreflective films to cover markers with.
    -I'm very interested in using retroreflective paint instead of film, but
    old posts in the archives indicate that the paint (if it's still even
    available), when properly applied is only about 10% as effective as the
    film. I don't think that this level of performance would be acceptable
    for my application. If you have any experience using any kind of
    retroreflective paint, I'd like to know how well it's worked in your
    application compared to the films. I'd also like to know where you got

    Thanks for any help you can offer- I'll summarize and post all


    Hi Brian,

    My experience is primarily with Vicon's 25 mm markers and larger, but I
    used with great success the 3M reflective tape both to repair existing
    markers and to make new custom markers. It's expensive, but one roll
    will last for a very long time. For the markers, I have used a variety
    of materials to make my own, but it depends on what kind of activity you
    are studying. For heavy activity, I had success with rubber bouncing
    balls and plastic golf balls and things of that nature, but for lighter
    activity styrofoam balls found in any craft store should work well and
    come in a greater variety of sizes. Marbles could also work, but you
    might have to have a drill press to devise a means of attaching them.
    It really does depend on the activity you are studying and how you want
    to affix the markers to your subjects, so if you have more info I might
    be able to come up with some better ideas. Hope any of this was


    Tiffany Zachry
    Moss Rehabilitation Research Institute


    I think you can go to a craft store and get small styrofoam spheres. I
    believe that 3M makes reflective tape to cover the spheres with.

    Patrick Sparto


    There have been several discussions on the BIOMCH-L listserv about this.
    Search the archive (URL is at the bottom of your previous message) for
    "reflect" or "marker" or something like that. I remember there were some
    detailed instructions, I think, from several researchers for making your
    own inexpensive markers, as well as pitfalls and helpful tips about
    getting the supplies and about reflective paint.

    We used 3M reflective tape, cut into small strips to cover the wooden
    spheres. It has worked very well. As I recall, a roll of the tape is
    pretty expensive ($200?), and they didn't sell it in any lesser amounts.
    We've made about 100 reflectors and only used about two meters of the

    Other than the wooden spheres from a crafts store, I don't have any
    other ideas. Sorry.

    Bruce Etnyre, Ph.D., P.T.
    Kinesiology Department
    Rice University

    Dear Dr. Schulz,

    Try Motion Lab Systems for 3M retroreflective tape:
    Mr. Edmund Cramp,

    Plastic Spheres (Nylon):

    Best regards from Brazil,
    Wagner de Godoy

    Hi Brian,

    Small Parts Inc has the balls (spherically speaking) -

    Motion Lab Systems can supply the 3M coating materials - and I can talk
    you through some short-cuts in actually coating the balls. It's not as
    hard as you might think.

    Retroreflective paint does work but is significantly less reflective
    than the film ... I think Qualysis used the paint at one time.

    We always carry a stock of 1" tape and have some 3" wide tape too. We
    can order other sizes but we have to order by the roll so it's not
    really economic unless you need a LOT of tape. The 1" tape is $5.75 per

    Edmund Cramp -
    Motion Lab Systems, Inc. -
    15045 Old Hammond Highway, Baton Rouge, LA 70816 USA
    Tel: (Central Time Zone, GMT-6)

    An alternative pre-made marker supplier is:
    Kevin Krohn

    -Jeremy Determan

    Good morning.

    We hope to have our new website up soon. In the meantime, I've attached
    a price list & pictures for all MoCap Solution's new custom items. On
    the new list are all the items that we plan on keeping in stock for same
    day customer shipments.

    Please let me know if there are OTHER parts that you have a large
    quantity/ substantial need for and we will be more than happy to quote
    them individually.

    MoCap Solutions highly engineered markers are injection molded from
    space age Liquid Silicone Rubber (LSR), an extremely durable yet
    flexible material. This allows the markers to fit against the human form
    comfortably yet remain intact during even the harshest motion capture

    MoCap Solution's new Z Suits, E-Z patches and Skinz Patches are awesome
    new designs and are made of very high quality materials.

    The new Z Suit is made of a new high quality 4 x 4 stretch breathable
    poly pro material. The 4 x 4 material is very cool and comfortable for
    the actor and also very durable for marker application & removal.

    The new E-Z patches are to be used with our 14 & 19mm markers when
    attaching them to Motion Capture suits. The small tab at each end of the
    E-Z patch makes it allot easier to remove than patches of the past. They
    can be made in black, red, blue, green and yellow to make it easier to
    identify the actors who are wearing the different colors.

    The new Skinz Patches are also to be used with our 14mm or 19mm marker
    (made without Velcro backing) directly on the capture subjects skin.
    Peel the self adhesive backing off of the skinz patch and place over the
    entire marker base. The patches are made from the same breathable fabric
    as band-aids.
    They hold the marker firmly in place, don't fall off from perspiration
    and can be easily removed after the capture session.

    Please let me know if you have any other questions or feed back
    regarding any items on the price list.

    Thank you!


    Kevin Krohn
    Business Development Manager

    United States Plastic Corp. ( sells spheres as small
    as 3/8".
    **Thin** coats of Sphere Brite (
    retroreflective spray paint have worked well in our applications. One
    $30 can has covered 100 markers so far and isn't empty yet.

    Doug Powell
    University of Texas Permian Basin

    Dear Brian,

    I faced the same problem some time ago in Germany.
    Finally y bought plastic (PVC) spheres originally made for bearings in
    washmachines or any other "watered" application. So the supplier was a
    bearing manufacturer. The spheres were quite cheap.
    I had no luck with paint (did not try it physically but searched a lot
    and talked to many people).
    Finally I used retroreflective film from Scotch 3M.
    Depending on how many markers you need, as they are small it will
    probably be enough to get some samples. Recently vendors here in Spain,
    were I'm now, provided me with some free samples. Not all suitable, but
    some of them. I think I could easily make about 20 markers from the
    samples I got.

    By the way, if you're going to build them yourself, the best way I found
    to do that is to cut tiny "daisies" (8 petals) out of the reflecting

    Hope this helped a bit.

    Good luck and have fun doing handicrafts,

    Gaspar Morey

    Hi Brian,

    We have been very happy with the markers we get from 3X3 designs here in
    Vancouver. Norma makes markers for the animation industry and is very
    good at making what you want. We recently purchased 50 9.5 mm markers
    with a .8 cm base and 50 12.5 cm markers with a 1.2 cm base for a very
    reasonable price. I noticed on her price list she makes markers as
    small as 4mm up to 25mm. Here is her contact info.

    T604) 777-2555
    F604) 777-2508

    Regards, Alec
    __________________________________________________ ___
    Alec Black
    Director, Shriners Gait Lab
    Sunny Hill Health Centre for Children
    3644 Slocan St.
    Vancouver, B.C.
    V5M 3E8

    Hello Brian,

    Please ask BTS Bioengineering:

    They make and offer this kind of markers. Maybe they can help.

    Alex Czarowicz | VP Sales & Marketing
    Organic Motion, Inc.


    We made up our own markers with reflective tape wrapped around stryofoam
    balls that we purchased from a handicrafts store. We then used small
    screws to attach the balls to a small plastic "platform" which could
    have two sided tape attach the balls to the subject. It worked fairly
    well for several years until eventually the screws pulled out. As the
    whole set up cost approximately $15 for 20 reflective markers we thought
    it worked well. At that price replacing them more often is still much
    cheaper than buying premade ones. I don't recall if we had any markers
    as small as you are planning on.

    Randall L. Jensen, PhD, FACSM, CSCS
    Professor of Sport & Execise Science
    Dept. HPER
    Northern Michigan University
    Marquette, MI 49855 USA

    I've always made my own markers, 20 mm ones for human applications and 6
    mm ones for cats.

    I used wooden beads for the 20 mm markers. You can buy the beads at arts
    and crafts stores like Michaels. The are pre-drilled and you can tap the
    hole if you want. Sure the hole goes all the way through, so the top
    will be a bit flattened. If you really want you can probably fill the
    wholes on one side, but I just taped them over with the reflective film.
    The reflective tape to use is 3M Scotchlite 7610 or 8850, it's self
    adhesive and super reflective and flexible enough to conform to the
    balls (I believe I used the 8850 in Belgium and the 7610 in the US, both
    look similar).
    I use a method that covers 1 ball with 3 pieces of tape: 2 rounds and 1
    rectangular strip.
    I use a round chisel (a leather tool that you can buy in tool shops) to
    cut rounds out of the tape.
    Then I make 6 radial cuts with a straight chisel (you can stack 3 or 4
    together), leaving the center part uncut.
    Apply 1 round to each pole of the ball while overlapping the flaps of
    tape nicely at the equator. Finnish off with a band around the equator.

    Cheapest markers ever...all it takes is the 3M tape and a bit of work,
    but with practice you can probably make a marker in 3 minutes !

    Good luck !

    Dirk Everaert, PhD, PT
    Research Associate
    University of Alberta
    Centre for Neuroscience
    513 Heritage Medical Research Centre
    Edmonton, Alberta T6G 2S2

    Ok, I was thinking about your scenario more over lunch, and I may have
    some ideas that could work for you. One is slightly unorthodox, the
    other very unorthodox but possibly a perfect solution. First, at any
    craft store like Michael's you can get wooden, glass, and plastic beads
    in various shapes, and they all already have a hole in them that could
    be used to attach to your threaded rods (they wouldn't screw in, but you
    could use glue or something else less permanent like a soft putty). The
    other idea is a little out there, but it could work quite well if you
    can find a place that will let you order in bulk. The end cap of
    certain body jewelry such as tongue rings is about the size that you're
    looking for, and the best part of them for your situation is that they
    come pre-threaded because they are made to screw onto the end of a rod.
    They also come in different gauges, so you should be able to find the
    size that is appropriate for the rods that are attached to your shoes.
    I actually wish I had thought of this a long time ago because it is a
    very neat solution to a problem we've all dealth with when doing motion
    capture. However, I think either solution should accomplish what you're
    trying to do and shouldn't be too costly, either. I hope this helps,
    and thanks for asking the question - it was nice to relive the days when
    I got to do fun stuff like mocap and EMG.

    I found a website for you that sells body jewelry wholesale. It looks
    like you can get the little acrylic ones for about $0.25 - $0.75 a
    piece, and you can buy as few as one. I know from experience that that
    price rivals the cost of the beads, but what you would want to do is
    take one of your rods into a piercing store and ask them if they can
    tell you what gauge it is so you can order the right size. The beads
    will probably work well, too, but the down side is that the holes don't
    come in different sizes and they're not threaded. You'll have to let me
    know which way you decide to go and how it works out.


    Tiffany Zachry
    Moss Rehabilitation Research Institute


    I've used retroreflective markers from BTS
    ( several years ago. They are
    generally 10mm in diameter. But they've also got some really tiny ones
    for finger movement. Their website has 3-20mm markers listed. I am not
    sure how much they cost now. But they worked well before.

    Hope it helps.

    Gang Yang

    Biodynamics Laboratory
    The Ohio State University
    Columbus, OH 43210


    I am not sure about the films, we always had it available in the Lab
    (UNSW), so I never had to look for them, but as for the spherical
    markers I used to get them done by a fitter machinist. Any CNC fitter
    could actually machine any size and material marker for you.

    hope this helps a bit


    Raul Landeo

    The most cost effective way is to make them yourself. We had our interns
    spend a day or two making 50 markers. All you need is 3M reflective tape
    (they sell them by the roll) and sphere or cube beads that can be bought
    at any crafts store (ie, Michaels). And you also need either vinyl
    padding or rubber mats for the base.

    Arnel Aguinaldo, MA, ATC
    Director, Center for Human Performance
    3020 Childrens Way 5054
    San Diego, CA 92123