5 Replies Latest reply on Jul 22, 2011 11:38 AM by Danny Sillett

    Odd surface ripple with a loft...

    Rich Bolduc

      Any clue how to fix it?  I've tried adjusting the curves and stuff but it seems to stay there.

        • Re: Odd surface ripple with a loft...
          Dan Riffell

          Which ripple are you concerned about?

          • Re: Odd surface ripple with a loft...
            Andrew Smith

            Rich,

             

            You are trying to make too complex a surface with a single feature (Surface-Loft6 in your part). Model a shape like this with several separate surfaces with co-incident edges, which may or may not be constrained tangent or curvature continuous to get the form you want.

             

            That shape I would model in quarters using lofts or surface fills, and several guide curves. Near the end, mirror the symmetrical sides over.

             

            Note: You don't usually need your sketches to lie atop previously created surfaces (Sketch2 extends onto Surface-Extrude2). In some cases this will confuse SW and screw up your feature. If you need it to specify an angle / tangency the make that segment "construction geometry" so SW will not try to include it in the surface mesh of the new feature.

             

            Hope that helps,

             

            Andrew

            • Re: Odd surface ripple with a loft...
              Danny Sillett

              In addition to what Andrew said on all accounts, if you absolutely feel you need to create that shape in one loft, but you've got one weird area that comes out with a ripple in it, there's another way around it.  This happens to me on occasion, sometimes I can back up & surface things in sections, sometimes it would add way too much complexity to do so.

               

              I think that that ripple may be coming from Sketch 2 having that line that extends onto the extruded surface as mentioned.  When you create the loft, SW might use the bottom vertex of the line in that sketch as an influence in the loft and possibly cause it to pull the surface around on you.  Changing that line to construction geo would probably fix it.  I've noticed this is also evident with using points in some sketches.  Say you have a series of points that are used to help you draw a sketch, but are off the sketch geo in some other spot in space and relate to some other sketch or edge.  Those points will influence the shapes of fill surfaces, even though they are not really technically a piece of the sketch's geometry.

               

              Anyhow, on to fixing your problem from another perspective.  If you're satisfied with the surface after using a single loft with the exception of one spot that sucks for one reason or another, you can try this.  Create a sketch that encompasses the ripple when looking down on it from the top, maybe a rectangle or ellipse or whatever works.  Then use that sketch to create a split line on that surface.  From there, use the Delete Face feature to get rid of that bad chunk.  You may opt to allow SW to delete and fill with a tangent surface, but the surface it automatically fills in may or may not be satisfactory.  So you may opt to just have SW delete the face, eliminating the ripple, but leaving you with an open surface body.  From there, you can create a surface fill, maybe using a couple of guide curves you create to build a patch surface that isnt all rippled.  When doing so, select the option to merge the result and try to form a solid to get your part back to solid.

               

              Hope that wall of text helps.