6 Replies Latest reply on Apr 22, 2014 11:59 PM by Mark Biasotti

    Cannot knit surfaces

    Leo Galang

      Hi everyone


      I'm kinda new to surface modelling in SW and I'm trying to model a lobetype pressure vessel, which has partitions between lobes. I've been trying to knit the surfaces so I eventually end up with a merged model. So far I've been using the Check feature to see where I have open surfaces, yet when I try to knit & merge the surfaces that are open I keep getting the error "The selected faces and surfaces cannot be knitted into one surface" and I'm kinda lost to what I should do to solve this problem. I can knit the outer surfaces together, but when it comes to knitting the partitions to the outer surfaces I get this problem.


      The whole point of doing this modelling is to load my model as an IGES file into Ansys Mechanical and do a FE analysis. If it helps I've attached the file.


      Can anyone here please help me with this problem?




      - Leo

        • Re: Cannot knit surfaces

          Hi Leo,


          Just go to Insert>Surface>knit and select all the surface bodies (in the surface body folder in the feature manager) EXCEPT "surface_trim29[1]" and "surface_trim29[2]".  Now you'll have a single solid volume.



            • Re: Cannot knit surfaces
              Leo Galang

              Hi Mark


              Just want to say thanks for the quick reply it's greatly appreciated. The thing is I need to include "surface_trim29[1]" and "surface_trim29[2]" to the single solid volume, since these "partition" is a necessary part of the FE analysis I'm gonna do afterwards.


              Can it be that the problem is due to the fact that I have 2 arc'ed surfaces and a straight one that intersects at the same point?

                • Re: Cannot knit surfaces

                  H Leo,


                  Understood, then go ahead an shell the main volume (that is knited) by the wall thickness you need. then do a thicken of surface_trim29[1] and surface_trim29[2] to create your partions.


                  the reason you can not knit it all at once (like your first request) is that it is impossible for parasolids to knit three surface edges togther.


                • Re: Cannot knit surfaces
                  Aryati Kamalrudin

                  Hye Mark,


                  I am also new to SW. I watched the videos in youtube to convert surfaces into solid but again, I had the same problem with Leo. I tried to knitted all the surfaces altogether to form solid but yet it ended up only able to merge. However, when I tried to merge those knitted-surface, an error occured saying the rebuild errors. I don't know how to solve the problem. Can you please help me to take a look at the file. Below is the attached of my file. Thanks in advance.



                • Re: Cannot knit surfaces
                  Jerry Steiger



                  I assume that you need to keep your model as surfaces so that you can use a Shell model in your FEA. In that case you will have to leave your internal partitions as separate surfaces, since SolidWorks can't have a single surface at a T where surfaces meet. This shouldn't be a problem with your FEA software, you will just have to tell it to bond the edges.


                  Jerry S.