Welcome to the Onshape forum! Ask questions and join in the discussions about everything Onshape.

First time visiting? Here are some places to start:
  1. Looking for a certain topic? Check out the categories filter or use Search (upper right).
  2. Need support? Ask a question to our Community Support category.
  3. Please submit support tickets for bugs but you can request improvements in the Product Feedback category.
  4. Be respectful, on topic and if you see a problem, Flag it.

If you would like to contact our Community Manager personally, feel free to send a private message or an email.

Wire moves relative to part sliding

I am trying to design a telescoping boom of a mobile crane, where the boom extension is controlled by a wire and I would like to simulate the telescope behavior of all participating parts in relationship to the movement.

I can simulate the telescope behaviour of the two components with the slide mate connector and a linear relationship between them:

When the 2 part of the boom are moved, the overall wire length remains the same, but the distance between the anchor points in the back (read arrows) and the guide pulley in the front (green arrow) should change, which I cannot currently achieve.

Is this something, which can be designed and simulated with Onshape?

If this is the case, can someone point me to a tutorial or description, how this can be achieved?

I appreciate any advise or help to address this design challenge!

Best regards

Gerald Kreissig


  • wayne_sauderwayne_sauder Member, Simulation EVP Posts: 282 PRO
    I have not played with wire or rope, but I did spend a long time trying to get a conveyor chain to simulate for me. Never did get it, from what I understand such things would require a type of contact and release mate, which Onshape does not currently have. However, if you can figure out how to make it work I would be interested in knowing how it is done.
  • john_mcclaryjohn_mcclary Member, Developers Posts: 3,693 PRO
    You won't be able to show the wire being wound up in real time. But you can configure the part's lengths and show the positions you need. 
  • gerald_kreissiggerald_kreissig Member Posts: 8
    edited April 2020

    I came up with this idea too and had already implemented it:

    It works as expected, but it is missing the thrill of realtime movement!

  • john_mcclaryjohn_mcclary Member, Developers Posts: 3,693 PRO
    edited April 2020
    Well, because your wire is straight, you can take advantage of overlapping wires if you really want an animate-able model.

    it won't work for a festoon or spring though.


  • gerald_kreissiggerald_kreissig Member Posts: 8
    That's neat!
    Thank you for the idea - I will try it!
  • gerald_kreissiggerald_kreissig Member Posts: 8

    Hello John,
    I tried your idea of using the linear movement of wire segments as you have shown it with the light sabre:

    It works just as I had envisioned it!
    Thank you, Gerald
  • john_mcclaryjohn_mcclary Member, Developers Posts: 3,693 PRO
Sign In or Register to comment.