6 Replies Latest reply on Aug 8, 2018 7:10 PM by Armand Matossian

    Curvature Analysis

    Armand Matossian

      I created a basic surface that is controlled with 2D splines. I am not sure why the change in curvature is so dramatic. All edges splines are tangent. It is causing issues with a fillet around the upper edge after the surface is thickened.

        • Re: Curvature Analysis
          Ian Moore

          What feature did you use to create the spout section? It looks like you have used either a boundary surface or a filled surface with the "optimize surface" box selected, or perhaps even a loft. Try using a filled surface with the "optimize surface" de-selected.

           

          Can you show your feature tree or attach your SW file? In general, you don't want to use the edge of a curved Surface Thicken for a final product. It's not a very reliable or robust type modeling practice. It's better to make the solid body first and cut the edges to shape.

            • Re: Curvature Analysis
              Armand Matossian

              Hey Ian,

               

              I uploaded the SW file and the feature tree. I am having other issues with the surface thicken tool on another part. I would think this would be simple enough. Especially because the problem I am having is within the surface and not the edge.

                • Re: Curvature Analysis
                  Ian Moore

                  Ok, there are a few issues here and they're compounding a bit.

                   

                  First off, like I said, I'd do trims and cuts after your thicken. The wonky surface that you're seeing here is a result of the thicken feature trying to create a normal surface to a complex 3D curve:

                  Surface.PNG

                   

                  If you create the basic shape first:

                  Base.PNG

                  And then trim and fillet, you'll have a much more robust part:

                  Trim.PNGFillet.PNG

                   

                  Ok, so that should help with some of the thicken stuff. I'll do a separate response for that particular surface you're having issues with.

                  • Re: Curvature Analysis
                    Ian Moore

                    When creating loft like you have, the loft is trying wrap a square grid onto a complex surface. This is fine for relatively square surfaces, but it doesn't take much to throw the square blanket off. As it tries to pull the shape toward the corners or tangent edges, it "pinches" to fit it. You can especially see it in creases at the edges (a little bit on the top and right edge here). I've shown the squares here by turning on the "mesh preview". This is a surface fill feature, but it's doing the same thing as a boundary surface or loft.

                     

                    Mesh Boundary optimize.PNG

                     

                    Alternatively, if you take off the "optimize surface" feature, what Solidworks does is just lay a blanket in whatever way fits best, and then trims it at your selected border. It doesn't try to pinch the squares in to fit.

                     

                    Notice I'm also using an extruded "helper surface" rather than doing "normal to" a sketch as you did. This is common practice when getting into more advanced surfacing.

                    Mesh boundary.PNG