9 Replies Latest reply on Sep 19, 2011 10:11 AM by Bob Jones

    How to "configure" a sketch

    Bob Jones

      I have a sketch that is used in a sweep as a path. The cross section is just a rectangle and the path sketch is just an "S". The sweep is used in several other features down the tree such as a linear pattern and circular pattern as well as some fillets and such.

       

      Now I want to be able to change the sketch for the path from an S into a straight light. This shouldn't in any way effect the features further down the line. I need to "configure" the sketch, or rather use one or the other depending on the configuration.

       

      The reason I would like to do this is that I do not want to duplicate all the features applied to the sweep since it is unecessary. I cannot dimension the "S" since it is a spline(AFAIK).

       

      Is this possible?

       

      What I would really like to do is be able to suppress/unsuppress the line segments in the sketch used for the sweep path. Or toggle(in the DT) between two sweep paths.

        • Re: How to "configure" a sketch
          Mark Kaiser

          I think this one is a not possible.  You can configure dimensions, suppress/unsuppress features and sketches, but I don't think you can change the path of a sweep from curvy to straight for different configs.  Not sure of a workaround for it either.

          • Re: How to "configure" a sketch
            Deepak Gupta

            NO way to do that. The only option might be to create multiple files with required sketches.

            • Re: How to "configure" a sketch
              Nick Goodrum

              Depending on the complexity of the part, you may be able to us the Deform command and transform you S shape into a straight line. From there you could have two configurations; one with the Deform command surpressed, one without....

               

              Regards

              NG

              • Re: How to "configure" a sketch
                Charles Culp

                You can suppress sketch relations. Edit a sketch, then Tools>Relations>Display/Delete. This will allow you to select a sketch relation, then you can use the Suppressed option to suppress it. In order for this to work you will have to dimension the spline.

                 

                I suggest having two different S features. First, draw the "S", then, in a new sketch draw a more different "S". Create seperate features from each, and then suppress those features to control configurations. This will require careful organization of later relations, but you should be able to create reference planes/etc for your references instead of the faces of the features themselves. I'd have to see the file to comment further.

                  • Re: How to "configure" a sketch
                    Bob Jones

                    Essentially I just want to draw an S curve OR straight line using a sweep feature with a rectangular cross section. The S curve is really a logistics like function... that is, it doesn't bend back on itself.

                     

                    My initial method was to use line segments and arcs that were based off of a shape like

                     

                           ___

                          /

                    __/

                     

                     

                    and just give it "fillet" like corners using arcs. In fact using the above would work if I could allow self intersections of the sweep path and then fillet afterwards.

                     

                    But I also need to turn that into

                     

                     

                    ----------

                     

                     

                    and have all the features build off it use the new version. (or else I have to duplicate everything which is a huge waste of time since both shapes should not produce any errors since they are so simple and used in a simple way)

                     

                    The new method I'm working on is to use a fit spline but I cannot control the "arc radius" like I could in the other method. I know the spline has control modifiers but these don't seem to be easily controlled.

                    By using a fit spline to the above "S" shape I get low radii arcs for the corners that don't seem to be easily controlled. I need much smoother corners. Best I can tell is the fit spline is trying to fit the complete line segments instead of end or mid points.  I think I can add a few extra line segments to make it work.

                     

                    Alternatively I mnight just be able to use the linear "S" shape drawn above with 3 extrudes and fillet afterwards. This requires at least 4 sketches though.

                     

                    Can you suppress such a relation using a DT? Ultimately I'm trying to controll all this using a DT with as few entries as possible.

                     

                    +:

                     

                    If I use

                             ____

                            /

                           /*

                    ___/

                     

                    Where * and the ___ are used in the fit spline(and not the two /'s) then I can get much better control over the smoothness. The only problem now is making it "natural" so it looks like arcs. I'm sure there is some mathematical relationship between the lengths and angles of the /'s that will make it work.

                     

                    It seems like this works. The angles are 45's and the lengths should be symmetric on the two /'s. By controlling the angle and length of /* we can get the desired smoothness. It shouldn't be hard to turn this into a straight light by changing the angles.

                      • Re: How to "configure" a sketch
                        Peter Gumprecht

                        Bob,

                        Here is a suggestion. Instead of curves use a spline with two lines at each end(or not). Then use a dimension between the spline endpoints to drive the height. First be sure to constrain the spline end points in the horizontal plane. To make it flat just imput a zero dimension for the height. Hope this helps. See below

                         

                        Pete

                         

                        spline with height:

                        spline height.png

                        and spline flat:

                        spline flat.png

                          • Re: How to "configure" a sketch
                            Bob Jones

                            Thats basically what I did but I used a line segment inbetween to be able to control the smoothness. Initially I was using all the line segments because I didn't know any better. I think it will work. It would be nice if there was a way to control the "fit" with a single parameter but I think using two controll variables will do.

                            S Spline.png

                      • Re: How to "configure" a sketch
                        Mauricio Martinez-Saez

                        Bob Jones wrote:

                         

                        I have a sketch that is used in a sweep as a path. The cross section is just a rectangle and the path sketch is just an "S". The sweep is used in several other features down the tree such as a linear pattern and circular pattern as well as some fillets and such.

                         

                        Now I want to be able to change the sketch for the path from an S into a straight light. This shouldn't in any way effect the features further down the line. I need to "configure" the sketch, or rather use one or the other depending on the configuration.

                         

                        The reason I would like to do this is that I do not want to duplicate all the features applied to the sweep since it is unecessary. I cannot dimension the "S" since it is a spline(AFAIK).

                         

                        Is this possible?

                         

                        What I would really like to do is be able to suppress/unsuppress the line segments in the sketch used for the sweep path. Or toggle(in the DT) between two sweep paths.

                        Yes is possible, using dimensions which then can be driven by relations, equations or by a design table.  This is what you do...

                         

                        1.- Create a sketch as show on the following graph (a copy of a part file containing the sketch is attached)...

                        Spline-01.JPG

                        Then you select the two "gren" lines and the "blue" line as show on the following graph...

                        Spline-02.JPG

                        With those lines selected you create a "fit spline" as show on the following graph..

                        Spline-03.JPG

                        Once the Fit Spline is created, you can control the size and shape of the "S",  making it large...

                        Spline-04.JPG

                        or small...

                        Spline-05.JPG

                        By changing the values on the dimensions marked on yellow... or...

                        Spline-06.JPG

                        you can convert the sketch to a straight line, by entering a value of 1 on "H" (the value of 1 on the aux. dim. market on blue, is to avoid entering "0" on "H" since when you do that sometimes SolidWorks "reverse" the geometry if you enter a value larger that "0" (after entering "0") since the value do not have sign.

                         

                        Hope this serve to resolve your issue.

                         

                        M.G. Martinez-Saez