5 Replies Latest reply on Jul 24, 2017 1:36 PM by Anton Petrov

    Flipping connectors in boundary surfaces.

    Anton Petrov

      Why does solidworks sometimes flip connectors in boundary surfaces on rebuilds?  Any way to prevent this from happening?  Sometimes the boundary blend fails and all i have to do is flip the connectors to fix it.  But often the downstream features are now connected to flipped edges because the boundary blend was flipped so i have to go through the tree and fix every failed feature.  It happens again when i have to make small changes to something up the tree above the offending boundary blend. I am guessing the reason for this is probably buried deep inside solidworks code alongside all the other obscure bugs and behaviors that continue making their way into each new and "improved" solidworks version.  Ah if only i had the time to learn some other cad package....

        • Re: Flipping connectors in boundary surfaces.
          Boyko Tchavdarov

          It flips also relations to the end point of a linear segment and arcs spanned between two points.

          • Re: Flipping connectors in boundary surfaces.
            Anton Petrov

            Version 2017 and the bug is still there (along with many others).  Really wish Solidworks would stop adding stupid features that no one needs or asking for and fix the bugs that have been there for many years.  I am guessing that at this point the code is such a mess that no solidworks engineer dares to attempt to fix it.  Meanwhile we keep paying $ every year....

            • Re: Flipping connectors in boundary surfaces.
              Mark Landsaat

              Hi Anton,

               

              My belief is that this happens due to opposing edges not having matching directions. If you try to create a boundary surface between two surfaces each of the input surfaces has a UV direction. If these don't match the boundary surface can get confused and map the end points to opposite locations. The same is true for curves. Curves have a direction and if the direction of the input curves don't match the surface can flip on itself during rebuild.

               

              I am no expert in this, so we would need someone from SWX to confirm that this is happening. However the reason I believe this to be true is due to the fact that this never happens in programs where you have control over the surface and curve direction. In both Rhino and ZW3D you can control the direction of the curves and surfaces to prevent this from happening.

               

              In addition to this ZW3D has an option in the boundary surface dialogue box to override the direction of input curves and edges to ensure everything is aligned. This input is sticky and as a result the surface never flips connectors upon rebuild. Check out the screenshot below. The red and green arrows represent the U and V direction of the input surfaces. The button with the blue and red arrow allows you to flip the direction in case they are not aligned. Just as an FYI, I have submitted this as an enhancement request for the Boundary Surface Command. In the mean time we will have to deal with flipped connectors upon rebuild.

              Boundary_Srf.JPG

                • Re: Flipping connectors in boundary surfaces.
                  Anton Petrov

                  Thanks, Mark.  Yeah perhaps that is the reason.  It would be nice to have some control over UV lines.  For example when creating boundary surfaces and aligning them with UV lines (align with ISO command), there is no way to select which iso lines you want to align them with - u or v.   In certain situations this is a problem as it automatically aligns itself with the undesired iso lines.