An alternative to XSI’s tail spring op

May 8th, 2008 by Helge Mathee - Viewed 31778 times -

Hey gang,

working on some characters with secondary motion I came up with a pretty simple spring op including some caching / plotting functionality and thought I’d share it.

It is a very basic radial spring, which comes with a DisplayInfo to control all parameters through the viewport. Additionally the objects created are put in groups for your convenience.

Here’s a video demonstrating the addon: (Encoded in Techsmith Camtasia, 51 MB)

And finally, here’s the link to the addon:

31 Responses to “An alternative to XSI’s tail spring op”

  1. Miquel says:

    Thank you,

    Very useful.


  2. niko says:

    Thanks Helge,

    I was working on a simple spring op like that for secondary motion as well (in Python though). I’m playing around with your’s to see if it could help me get further as I’m trying to make mine able to resume default state when it’s going at a constant speed in the same direction (same velocity). I didn’t think of adding a wind, nor a gravity like your’s. Very nice addition! It may well be the answer I was looking for. :)

    Thanks for the tool. Looking forward to test it more and inspect it.

  3. Thiago Costa says:

    Thats really good Helge, thanks.
    As always it’s gonna be very useful. :)

  4. MD says:

    Thanks a lot Helge, very useful!!

  5. Faker says:

    wow really nice and useful … thanks a lot


  6. Matt Lowery says:

    Many thanks Helge. This will come in very handy indeed!

  7. Very nice tool, Thanks a lot for sharing it.

  8. Moriarty says:

    Oh helge, you are my guru. ( deep bow.. )

  9. Moods says:

    i notice this function in your MT_RIGZ. : ) hoho~and i extract as a tool, similar to this one.

    i just post to say thanks, thank you for keep the MT_RIGZ open source. i learnd a lot.

  10. Really nice creative solution. I love it.

  11. Jae Ham says:

    This thing works Beautifully !!!!
    Thank you so much Helge !!!!

  12. gavin h says:

    the code is so intuitive.
    great work as usual

  13. punchatz says:

    Simply fantastic…I love the work flow for building the spring branches…perfect.

  14. justa_newbie says:

    Helge, this looks awesome, but is it only for v6.5? (I didn’t see it noted anywhere, so I tried to
    install as addon with v6.02, but no joy…)

  15. Richard says:

    @ justa_newbie

    Hi, it works fine for me here on foundation 6.02. Be sure to select the null and create a model before applying the springs (follow instructions on the video).

    Fantastic addon Helge. Thanks so much!


  16. Richard says:

    still @ justa_newbie

    Oh, and be sure not to be at frame 1 when moving the base, as its the reset frame. Say if you go at frame 5 and then move the spring base. Should work fine.

  17. justa_newbie says:

    thanks, Richard…still having an issue just installing it via File->Add-on->Install (I can find the addon,
    but the ‘install’ button is greyed-out)…if I install by just dragging into viewport, it shows up as an installed addon, but the MindThink toolbar doesn’t exist for me to even access. Never had a problem installing 3DQuakers or squid’s UVLayout plugins…prolly some newb error on my part tho. Will keep trying.

  18. Helge Mathee says:

    @ justa_newbie

    I don’t have those issues. I tried to reproduce them on 6.02 but no luck. Maybe reinstall XSI or delete the user folder, I don’t understand what you are experiencing. Good luck.

  19. Pete says:

    Hi there,
    THanks so much for this cool tool!
    One question however, once you have created the spring objects, is it possible to adjust the point they pivot around in order to fit it to my rig? I understand there is the option to scale the chain elements but the first bone doesn’t seem to pivot from the center of the first null.

  20. khanibal says:

    Fantastic! I can at least apply a good secondary motion to my characters !
    Works fine!
    Thanks a lot!

  21. Chris says:

    Hi there,

    I’m using the spring addon and its great, but beyond a certain scale it gets unstable. Even when I scale the root null in a new scene it becomes unstable. Any help would be appreciated?



  22. sam says:

    what glorious fun this is.
    im going to attempt to assign it to a bunch of preexisting bones, or perhaps just read positions/ rotations and bone lengths from preexisting bones.
    thanks helge, Its fantastic to see things like this done with production in mind.

  23. Nice work Helge.
    We are using it now on a hair setup to get secondary motion working.
    So far its holding up really well in our referenced asset pipeline.

  24. Harry says:

    Im using the mt spring op for the first time, works great, very quick and simple.
    but i cant seem to get mirrored sym. The method i use works but gives different dyn result for each side, (i duplicated my null, with Shared parrent on, & freeze negative scale off, then set neutral pose for the duplicated ob.., then created springs) is this wrong.
    ps i need to get this duplicate sym work today if posible for this project.
    can any one HELP!!!!!!!!!!!!

  25. Helen says:

    God I’m so happy I found this. Thank you so much!
    I was getting there with the out of the box spring constaints, but this is so much more elegant and robust.

    You’re my springy hero.

    I’m rigging a fat character and will be using this to create jiggle.
    Will send link later.

  26. Archer} says:

    the files is not acessible for now… :(

  27. Pearl says:

    Hey guys, the link is not accessible anymore, please help would also like to use this..please if you can forward the right link.

  28. christian says:

    found the mt_addon here:

  29. Ariel says:


    i ve been using the spring for a while and i found something strange. The parameters sometimes will all disappear except size and length……well, the spring is still working but i cant adjust the parameters any more. The only solution is to redo the settings…
    Do you know why this is happening and any way to show back the parameters?


  30. Christopher says:

    Thank you very much. Extremely helpful.