7 Replies Latest reply on Feb 13, 2009 5:48 PM by Jeff Mowry

    Knitting Issues

    Raj Deshpande
      I imported a legacy part ("Top Housing Before") that I would like to modify (see highlighted "blue" surfaces). Using Import Diagnostics I deleted faces and then tried to recreate new faces by patching the 3D sketches and remaining surfaces ("Top Housing After"). I was able to knit most of the surfaces except the two surfaces highlighted in "red". I tried several methods (tried to split and patch smaller areas) without success. I can see small gaps between the surfaces but I was unable to heal the gaps.

      I have had few other issues with surfacing.
      1. Once I started adding the features to imported part, I was unable to go back to Import Diagnostics (the option was suppressed) and modify imported surface. I had to delete all the features/changes (suppressing the features or rolling back did not work) before I could go back and modify the imported surface again. It would have saved some time if I could use Import Diagnostic tool interactively.
      2. Once I stated knitting the surfaces, other near by surfaces started shifting. Please see screen shots before and after knitting. Is it something typical?
      3. How does on pinpoint area or highlight surfaces that are causing problems? (e.g. in Import Diagnostics the invalid faces and gaps are highlighted). I tried using Tools/System Option/Performance/verification on rebuild without success.
      4. Is there a simpler or different method one can use to modify imported parts/surfaces?
      5. How do I minimize the file size? The file size increased in excess of 60+ Meg in one case.

      I would appreciate any help you can provide. Thank you.

      SW 2009 SP 2.0
      Dell Precision 380
      Intel Pentium 4 Processor, 300 GHz
      2 GB, 533 MHz, DDR2 SDRAM
      nVidia Quadro FX 3450, 256 MB PCIe

        • Knitting Issues
          Jeff Mowry
          I've not had time to download and view the issues you're seeing, but can suggest a possible fix without seeing the issue. Consider getting as far as you can with the surfaces, then exporting to parasolid format, then importing back into SolidWorks using the Import Diagnostics tool when re-importing. This might help out more incrementally, rather than trying to do it all in a single shot.

          What software created the original file? Perhaps you could get a "fresh" export from that application with some tweaked settings (such as resolution of curves/surfaces accuracy)?

            • Knitting Issues
              Raj Deshpande
              Hi Jeff,

              Thanks for your follow-up. I tried to export the part as Parasolid and imported it again in SW. It resolved issue with one of the face. However, other faces changed and I could not repair them. Thanks for your suggestion.

              As I stated in my earlier post, if SW allowed me to modify (e.g. split) the imported faces and then if I could delete split faces (instead of deleting whole faces in Import Diagnostics and trying to patch lager areas), then modifications to imported geometries would be lot simpler. I would also like to know why the faces/boundaries changed when I started knitting some of the faces (see screen shot).

              I think the part was originally modeled in Pro-E. I am not sure, because it predates my tenure and couple of company mergers. I should note that I was successful in modifying other two parts using the same technique.

              SW 2009 SP 2.0
              Dell Precision 380
              Intel Pentium 4 Processor, 300 GHz
              2 GB, 533 MHz, DDR2 SDRAM
              nVidia Quadro FX 3450, 256 MB PCIe
            • Knitting Issues
              Jeff Mowry
              I don't see a screen shot link. Meanwhile, in healing/knitting edges, I seem to remember some slight movement of some of the boundaries, too. But in a way, that makes sense--certainly if the edges aren't already coincident, they would have to move when joined. (Is this what you mean?)

              Here's a hack for splitting the surfaces:
              Offset the surfaces you want to use at 0.00" (duplicating your original surface body).
              Use a split line to split the original and copied surface body.
              Delete faces on one side of the split line for one surface body and on the other side of the split line for the other surface body.
              This will yield the same effect of splitting the surface, but without the convenience of having such a tool.

                • Knitting Issues
                  Raj Deshpande
                  Hi Jeff,

                  The screen shots are in the .zip folder I attached with the original post. You are right, the edges may move slightly. However, I would like to modify existing tool so that the changes are surgical. I would like to keep most of the untouched surfaces (mainly draft angles) intact. I liked your idea of offsetting/splitting the surfaces. I will try that. Thanks again for your time and suggestions.

                  SW 2009 SP 2.0
                  Dell Precision 380
                  Intel Pentium 4 Processor, 300 GHz
                  2 GB, 533 MHz, DDR2 SDRAM
                  nVidia Quadro FX 3450, 256 MB PCIe
                    • Knitting Issues
                      Raj Deshpande
                      Hi Jeff,

                      I was able to knit the surfaces and convert it into solid. I was also able to match the curvature of new surfaces closely to the old ones using several restraint curves.

                      Unfortunately, I tried so many things that I don't know what fixed the problem. My guess is that the order in which I picked the surfaces for knitting made some difference. Any way, I appreciated your help. I learned few new tricks. Thank you.

                      SW 2009 SP 2.0
                      Dell Precision 380
                      Intel Pentium 4 Processor, 300 GHz
                      2 GB, 533 MHz, DDR2 SDRAM
                      nVidia Quadro FX 3450, 256 MB PCIe
                        • Knitting Issues
                          lenny bucholz
                          Hey Jeff you and i would have done the same thing....It always takes a ID guy and a modelmaker to solve these issues. We seem to work all night to figure it out because it's our job.

                          what everyone needs to understand is, and i mean is!, every part, imported or not is different, what fixes on wont fix the other, imports are even more funky because all packages write there code for iges, step, parasolids and so on just a little different. also who modeled said parts, bad modeling produces bad iges or other formates.

                          i've had to deal with models fromPROE, Inventor, Rino, Mastercam, Surfcam, ACAD, SolidEdge and a slue of others and it's a crap shoot sometimes.

                          Lenny

                    • Knitting Issues
                      Jeff Mowry
                      r d, thanks for the update--glad something worked out, even if quite the hack. (You know, string enough hacks together and you've got a "method". Scary.)

                      Lenny, what's up? Long time, no see. You're totally right--another late night last night myself because of surface Trim failures in v2008. They work when built, but inexplicably fail after a rebuild. Then roll back before the trim, do exactly the same thing again, and new new Trim works fine. (Lame waste o time/sleep.) So sometimes even different versions of the SAME software will do this sort of thing, much less interpreting exports from other software types.