6 Replies Latest reply on Sep 27, 2016 12:13 PM by Dennis Dohogne

    Behavior of Limit Mates Seems Better in SWX2016

    Dennis Dohogne

      Maybe it is just me, but it seems that Limit Mates are behaving better in SWX2016 (SP4.0).  In the past I had a lot of trouble with Limit Mates applied in a subassembly and them causing problems in upper level assemblies.  For instance, we use a lot of pneumatic cylinders.  In the cylinder subassy I'll set up the following configurations: Retracted, Extended, and Stroke Limited.  The first two are static and the last one has a limit mate that allows travel between the retracted and extended states.  In working out the designs I would often change the states of the cylinder subassy between Retracted and Extended.  However, if I used the Stroke Limited configuration it would cause all kinds of issues, especially the higher up (more levels) I was in the top level assembly.  In order to get the top level mechanism to perform according to the limitations of the cylinder I had to create another cylinder configuration, Free, that had no limitations on the stroke.  I would then create a suitable limit mate in the top level assembly.  This is not how we should have to do it.  The Limit Mates should be applied at the lowest level possible so that it benefits anything using that subassembly.

       

      Well, I'm happy to report that Limit Mates seem to be performing as you would expect.  I have cylinder assemblies four levels down with all the associated assemblies set to flexible.  Using the Stroke Limited configuration I am not getting the yellow and red mate warnings I used to.

       

      Are any of you aware of a change made that accounts for this?  Have any of you experienced the same thing?

        • Re: Behavior of Limit Mates Seems Better in SWX2016
          Dennis Dohogne

          I have done this with a spring simulation and it seems to behave well in upper level assemblies also.  It has been an unfortunate problem since Limit Mates came out.

          • Re: Behavior of Limit Mates Seems Better in SWX2016
            Matt Peneguy

            Thank you for posting this! 
            We are currently using version 2014, but will be upgrading to 2016.  It really bothers me that sometimes the lower level limit mates would flip around or do really odd things.  I have had to resort to similar methods to get things to work "correctly".

            I am hoping we have a similar good outcome with the new version.

            I would give your post a "Like", but that option doesn't appear available for the first post in a discussion.  It only appears for replies.

            • Re: Behavior of Limit Mates Seems Better in SWX2016
              Leo Breevoort

              I'm still on SW2016 SP3, so I can't comment on SP4.

              I often have trouble with flexible sub-assemblies reaching the lower limit. While the sub-assembly itself works fine, when I put it in a higher lever assembly the flexible sub-assembly just doesn't rech the lower limit. It stays clear for just a couple of mm, either pulling it with the mouse or adding a mate. Sometimes mating the flexible sub-assembly to its lower limit works when I first create the higher level assembly, but re-opening it later often results in mate errors. Usually those mate errors can't be repaired, not by me at least.

              Is this what has been solved in SP4?

                • Re: Behavior of Limit Mates Seems Better in SWX2016
                  Dennis Dohogne

                  Leo Breevoort, I can't say if the better behavior I am seeing is something specifically implemented in SP4.0 or not.  I had installed SWX2016 SP0.0 and  did not like the bland UI so I left it alone until after SP4 had been out a couple weeks.

                   

                  The problem I had been seeing is that the limit mates when applied in the lowest level assembly would cause too many conflicts at the upper level.  Your problem sounds very different.  Is there the chance there are other things limiting the motion in your assembly?

                    • Re: Behavior of Limit Mates Seems Better in SWX2016
                      Leo Breevoort

                      This is one example with a simple telescopic guide (I do encounter the same problem with other parts like cilinders)

                       

                      The guide itself works fine and reaches its minimum limit as intended:

                      tel00.JPG

                       

                      When used in a higher assembly the guide refuses to go its lower limit and creates mate errors when forced to do so. There is nothing else restricting the movement. The only 'complicating factor' I can think of, is I use the same telescopic guide twice in the higher assembly, which may cause rebuild issues. But then again I'm forcing them both the same position.

                       

                      tel01.JPG

                       

                      I use a workaround now. I simply suppress the limit distance mate in in telescopic guide itself (so it can move freely) and the mate the desired position in the higher assembly.

                      This works fine, but in this way the guide can move to 'physically impossible' positions. It's okay if you know what you're doing, but when engineering complex movements/constructions it can be very helpfull to have the limit distance in place.