7 Replies Latest reply on Jul 14, 2011 9:30 AM by 1-4EQZK9

    symmetric loft

    Ping Gan
    Ping Gan Jul 12, 2011 7:48 PM

      Hi,

       

      I try to create a loft with guide line (see attached), this should be a symmetric loft, but I got this (see Attached below). I really don't know why, may be some option I didn't pick. Anybody can tell me why or how to correctlly create a symmetric loft.

       

      Thank you very much

       

      Ping

       

       

      Loft Sketch.JPGLofr-3D.JPG

        • Re: symmetric loft
          Scott McFadden
          Scott McFadden Jul 12, 2011 7:51 PM (in response to Ping Gan)

          Ping,

          To assure what you are looking for create the splined curve at all 4 quadrants of the

          circle.  Select the other 3 as additional profiles and that should give you what you are looking for.

            • Re: symmetric loft
              Ping Gan
              Ping Gan Jul 12, 2011 8:12 PM (in response to Scott McFadden)

              Thanks Scott

               

              I have to create another symmetric sketch then add to guide line, any way can get symmetric loft?

               

              Thanks

               

              Ping

                • Re: symmetric loft
                  Scott McFadden
                  Scott McFadden Jul 12, 2011 8:24 PM (in response to Ping Gan)

                  Ping,

                  Try copying and pasting the first sketch to the next plane

                  90° away.  Then to create the third and forth ones mirror the first and second.

                  The top circle is your guide curve.  You may want to add a circle at the bottom

                  as well for a second guide curve.

                   

                  Understand that sometimes you have to create all of this to get smooth geometry.

                    • Re: symmetric loft
                      Ping Gan
                      Ping Gan Jul 13, 2011 12:29 PM (in response to Scott McFadden)

                      Hi Scott

                       

                      I made a loft using 4 guide curves, the shape of model is very good, it is I wanted. But on the right side of model, the surface spilit to two part, Left side only one surface (see attached), I don't know why it is not symmetric, I use symmetric sketch on both side.

                       

                      Thanks

                       

                      Ping

                       

                      Loft_Sketch.JPG

                      Loft_Left.JPGLoft_Right.JPG

                        • Re: symmetric loft
                          Scott McFadden
                          Scott McFadden Jul 13, 2011 1:04 PM (in response to Ping Gan)

                          Part of it is you are going from a round to a square.

                          Looks better though.

                          I would also suggest that your profile sketches be one segment.

                          Use the fit spline command to do that in the spline toolbar.  For some

                          reason if the sketches have different start points or different numbers of segments

                          this messes with the smoothness of the model surface.

                           

                          I was just thinking, are the top circle and the bottom rectangle your

                          profiles or your guide curves?  They should be your profiles.  And use the

                          fit spline on the square so it is one segment.  Then use the side curves as your

                          guide curves.

                  • Re: symmetric loft
                    Charles Culp
                    Charles Culp Jul 13, 2011 3:52 PM (in response to Ping Gan)

                    Ping,

                     

                    Here is how I would do it. Without a guide curve at all.

                     

                    CircleToSquare.PNG

                      • Re: symmetric loft
                        1-4EQZK9 Jul 14, 2011 9:30 AM (in response to Charles Culp)

                        Hi Ping,

                         

                        In addition to Charles method, which is a good way to do it, the key to getting a symmetrical loft, and the edge transistion to occur the way you want it is to first assign 4 sketch points in your circle profile. When you do the bpundary, use "add connector" to snap four connectors to the sketch points that you just created.

                         

                        Regards

                         

                        Mark