5 Replies Latest reply on Mar 21, 2018 3:54 PM by Todd Blacksher Branched from an earlier discussion.

    Re: Multiple parts move when I only want to move 1.

    Justin Byerly

      Making it flexible worked but now I am confused to why it worked. If I put 4 sub-assemblies in an upper assembly, shouldn't they work as individual (rigid) sub assemblies? Why would they somehow be linked and force me to make them flexible?

        • Re: Multiple parts move when I only want to move 1.
          Josh Brady

          How parts act when they are not fully constrained is basically undefined.  I've never worked out how SW decides if things should move together or not.  Basically, if you care where things are, you need to constrain them to be there.

          • Re: Multiple parts move when I only want to move 1.
            S. Casale

            In an assembly, a flexible sub-assembly will move according the way the sub-assembly is constrained, and then how it is constrained in the assembly.

              • Re: Multiple parts move when I only want to move 1.
                Justin Byerly

                Sorry, this is a continuation of another conversation. To help you understand my situation and what I am truly asking, I am working with a track like system with mounts that can move to where they are needed. The file was fully constrained but the issue I was having was that I would try to move 1 mount and all the others would move with it. In the other conversation, the answer was to make the sub-assembly (all 4 of the same sub-assembly) flexible which fixed my issue. I dont know why it worked. In example.....

                 

                Lets say the rail is the upper assembly and i drop 4 sub-assemblies (mounts) into the file. I mate them to the rail and use limit mates to allow them to travel. They are all mated individually and not to each other so they all have full travel through out the whole rail. Without making them "flexible" they all moved in the process of moving one.

                  • Re: Multiple parts move when I only want to move 1.
                    Todd Blacksher

                    Justin Byerly wrote:

                     

                    Lets say the rail is the upper assembly and i drop 4 sub-assemblies (mounts) into the file. I mate them to the rail and use limit mates to allow them to travel. They are all mated individually and not to each other so they all have full travel through out the whole rail. Without making them "flexible" they all moved in the process of moving one.

                    I have had mixed results using multiple sub-assemblies with limit mates in the past.

                    (I believe that these issues have been resolved, but I haven't verified.)

                    My first thought is to create a "free" configuration of your sub-assembly - for this configuration, suppress the limit mate.

                    In the top level assembly, you can control which configuration of each sub-assembly is used - set (3) of them to "free" and see what happens.

                    It is a shot in the dark, but it helped when I would run into weird behavior with sub-assemblies.

                • Re: Multiple parts move when I only want to move 1.
                  Todd Blacksher

                  This is a gross oversimplification, but think of it like this:

                  Make a box as a part / Make a lid as a part / Make a hinge as an assembly (2 leafs and a pin)

                  Open the hinge assembly and add mates to do what you want - fix one leaf, and allow the other leaf to rotate.

                  Make a new assembly with box, lid, hinge assembly.

                  Fix the box, mate the fixed leaf of the hinge to the box, mate the other leaf to the lid.

                  As a fixed sub-assembly, the lid will not open, it will merely hold the position that the hinge was last rebuilt/saved in.

                  As a flexible sub-assembly, the lid will follow the mates of the hinge, and it will be able to rotate.