5 Replies Latest reply on Jun 15, 2010 9:03 AM by Gregor Cadman

    Knit is warping faces

    Gregor Cadman

      I'm creating a mold involving lots of boundary surfaces and I'm having issues where Knit Surface appears to change faces as they knit. Specifically, I'll have two surface edges that I will connect with a tangent boundary surface (so, there are no gaps at the touching edges, so Knit shouldn't have to do anything difficult). Then I'll knit the three together, and sometimes the change in the boundary surface is quite dramatic. The loss of tangency is causing issues downstream. Any suggestions on how to minimize or prevent this issue? I've attached before and after pictures of curvature of an example knit.knit_1.JPGknit_2.JPG

        • Re: Knit is warping faces
          Matt Lombard

          sw09 and sw10 may give different results for knitting. 09 has an option in the Knit propmgr called "minimal adjustment". It's not clear to me if this allows more or less "adjustment" than usual, but you might give it a try and see what it does for you. If you are using sw10, it has different options having to do with tolerances. I think this is generally used to get knits to work that don't work with the default settings. If you are using sw10 and getting the results you show, then you need to set the tolerance to a smaller number (more zeros after the ".")

           

          I believe that boundary is the best feature to be using in your situation, because it more accurately matches the input than loft. If you are using sketches as boundary profiles, you might consider trying edges, since edges appear to be more accurate than sketches.

          • Re: Knit is warping faces
            Robert Stupplebeen

            Try saving as separate parts and bring both into an assembly.  View sections.  You may (hopefully) be chasing noise for your application.  Curvature mapping does not always show what I would call real.  For example, revolve an ellipse and it looks all wacky at least it did in 2008.  I hope this helps.

            Rob Stupplebeen

              • Re: Knit is warping faces
                Gregor Cadman

                You guys are right - I didn't think it was a display issue (the faces look fine before the knit, why should they change appearance after the knit with the same display settings?). But if I do a section cut through the faces, everything looks better. As Rob said, apparently viewing curvature isn't always right. Thanks!