20 Replies Latest reply on Nov 17, 2009 11:02 AM by Emilio Graff

    No conic creation?

    Rhyc Sandberg
      I'm curious about a statement made in the topic "SolidWorks surfacing capabilities or lack thereof". The poster indicates that SolidWorks lacks conic creation capability and others responding to his post appear to confirm this lack of functionality.

      I'm sure it's because I don't have much experience on some of the other CAD packages, but what exactly is being referred to here?? Are there some conic surface tools that other CAD apps have?

      SolidWorks can certainly create bodies that have a "cone" surface - just revolve an angled line around a vertical axis - or extrude a cylinder with a draft. Those operations create bodies with "cone" surface types.

      So, what is the conic creation capability that SolidWorks lacks?

      Rhyc
        • No conic creation?
          Kelvin Lamport
          Conics refers to the shapes created by cutting cones at various angles.
          See http://math2.org/math/algebra/conics.htm for some simple visuals.

          Of the four main conic shapes, (Circles, Elipses, Parabolas and Hyperbolas) SolidWorks can handle the first three. For some people not having hyperbolas is apparently a big deal. For the majority of products it is of little to no concern.
            • No conic creation?
              genexxer genexxer
              "No inflection points" is a key attribute of surfaces in the aerospace industry. Hyperbolas provide this and are safe from parametric changes producing inflection points.
                • No conic creation?
                  Rhyc Sandberg
                  Thanks for the input.

                  So it sounds like the 'conic' referred to in that post is a curve creation tool that creates any type of conic, not just a parabola or just an ellipse. And, I would imagine, a better interface than the parabola and ellipse tools in SW. [this should probably be posted in Mark Biasotti's topic on examples of good interfaces - under the UI heading]

                  It would be interesting to hear SolidWorks position on this. I'm SURE that it would not be a difficult thing for the smart boys and girls at SolidWorks to come up with this tool.

                  Rhyc
              • No conic creation?
                Matt Lombard
                In general, the word "conic" is meant by most people the way Kelvin describes it, but some CAD softwares like Pro/E, Catia, VX, Alias, and probably several more use the word "conic" to refer to a type of curve which is defined by 3 points and a rho value. I believe the rho value allows you to adjust the shape by essentially tilting the conic section section plane. A rho of .5 gives a parabola, for example.

                To people who grow up using them, it is sometimes hard to conceive of life without them. Like telling someone from Pittsburgh to make a sentence without "younses" in it.

                Anyway, the rest of us seem to get by with just using splines rather than conics. I would welcome them if they were added to SW, and I'm sure eventually I'd develop specific needs for them. A conic is a more controlled, developed and in the end a more specific type of shape than a spline.

                Parabolas are almost impossible to manage in SW, maybe replacing the parabola with a conic would give more functionality and make it easier to control at the same time. Not that I ever use parabolas, although I use ellipses quite frequently.
                  • No conic creation?
                    John Burrill
                    Theoretically, a conic section could be used to define circles, ellipses, parabolas and hyperboles.
                    (OK, that last one was an exaggeration)
                    John
                      • No conic creation?
                        Matt Lombard

                        John Burrill wrote:

                         

                        ...hyperboles.

                        (OK, that last one was an exaggeration)

                        John

                        Very funny. That one almost got by me.
                          • No conic creation?
                            Rhyc Sandberg
                            John,

                            That one did get by me one the first read. Very clever and funny. I like it...

                            I would guess that this tool doesn't exist yet because there has not been enough request for it. Because, again, it wouldn't be too difficult for them to develop.

                            Just dreaming, but, what would be cool would be to have an area in this forum that was specifically for feature requests like this. It could have a list of requested features that the members would vote on - whether it is interesting to them or not. The more members that vote on a feature, the higher up the list it goes.

                            This would give SolidWorks some indication of how important a feature request is to it's users. Do they have any other way of finding this out?

                            Rhyc
                              • No conic creation?
                                Matt Lombard
                                SW touts the Enhancement Request process, but it is completely opaque to users, meaning that no one really knows what kinds of things are being requested and how many people are requesting it.

                                What you are asking for, a transparent wish list, is already available in its infancy at SolidMentor. Ben Eadie has done a great job putting this together.

                                http://solidmentor.com/modules/Wish_list/

                                You'll have to register to make a wish or vote, but there are lots of other resources on the site as well. Check it out.
                                • No conic creation?
                                  Paul Salvador
                                  This request has been well over 5 years old... although more and more ID users see the limitations or workarounds need to achieve a corner blend using SolidWorks.. still things have not changed.

                                  Why, because it's another obvious feature which very few people sit down and request.

                                  .. Mayority wins.
                                    • No conic creation?
                                      Jarrett Johnson
                                      Well I'm a bit behind the times, but I thought I'd throw in my 2 cents here. I've been able to make SolidWorks do conic lofting using old school manual drafting systems. I created a couple different [similar] versions. Anyway, they worked great for what I was doing. I used over 85 equations [controled by various driving spline sketchs] to get the surface contours I wanted.. at the end of the day.. I was happy w/ the results.. This was done is ~2005 [or maybe 04] and since then w/ the new tools.. I don't know if I'd go to all the effort to do it this way again.. I think I could get the same results w/ out resorting to these measures..

                                      Fwiw..
                                        • No conic creation?
                                          Matt Lombard
                                          Jarrett,

                                          Nice stuff. What part of it in particular did you have to use the equations for?

                                            • No conic creation?
                                              Jarrett Johnson

                                              matt lombard wrote:

                                               

                                              Jarrett,



                                              Nice stuff. What part of it in particular did you have to use the equations for?

                                              Sorry Matt, I forgot to turn the 'subscribe' button on.. so I missed your reply. I'd have to go back into the model to find the exact equations. It was a formula which used a driven dim from a construction sketch [a spline which I could drag the handles to adjust the conic shape of the body] the driven dimension was then applied to the section sketch which adjusted it's shape to be circular, parabolic or hyperbolic.. by using the spline to drive everything... I could get smooth transitions from para to hyper.. It's only been 3-4 yrs since I looked at the file

                                              J
                                          • No conic creation?
                                            Alessandro Frattini
                                            Hi,
                                            I called my friend who works at the department of Ferrari races and told me that they use only spline (CATIA).
                                            http://www.f1automotori.com/wp.../F_2008_011.jpg

                                            Even here aerodynamic is very important.
                                            Have you an practical example where it would be better to have the function hyperbola ?

                                            Thanks,
                                            Alessandro
                                              • No conic creation?
                                                Kevin Quigley

                                                Alessandro Frattini wrote:

                                                 

                                                Have you an practical example where it would be better to have the function hyperbola ?

                                                It is more of a visual thing than for precision aerodynamics. As Jeff says conics in other apps let you move the end points around and maintain the basic shape you are after. Alternatively you can keep the end points static and adjust the rho value to change the curve shape.

                                                Anybody who visited SWW2008 get the chance to ask SW exactly why conics are still not supported?
                                    • No conic creation?
                                      Jeff Mowry
                                      One thing nice about the conics used in other system is that you can set them and leave them alone. With splines, if I move geometry on the end points, the middle point(s) of the spline are stuck where I left them previously instead of being innately related to the endpoints of the spline. Yeah, I can add dimensions, but that will hose me for quick adjustments to the surface geometry. Another thing about the improvised splines in this case is the difficulty in certainly controlling inflection, etc. since the spline curves can appear to be what I need without being a more constrained form of a curve (can bend all over the place). As an industrial designer, I have loads of applications for conics. Without them I often use filled surfaces with tangency settings (hack).

                                        • No conic creation?
                                          Jerry Steiger
                                          Jeff,

                                          You can get part of what you want by setting a spline to "Proportional". As you move the end points, the spline keeps it shape. Once you get it in the new position you can turn proportional off and modify the shape.

                                          Jerry Steiger
                                        • No conic creation?
                                          Jeff Mowry
                                          Nice! I knew that not. Thanks!

                                          (But I'd still like conics in SW.)

                                          • Re: No conic creation?
                                            Emilio Graff

                                            We should get whoever requested the ellipse to request it. He even got them to calculate the tangent... holy smokes! Obviously the parabola guy didn't have enough clout, since you can't draw the tangent to a parabola.

                                             

                                            Equations are nice, but not if the shape of the curve is defined by other entities in the sketch.

                                              • Re: No conic creation?
                                                Emilio Graff

                                                I created an ehancement request. Search for "conic" or "hyperbola". I also created one for tangents to conics, since you can only do it to a circle and an ellipse right now.

                                                 

                                                The hyperbola request is ER# 1-1413855312

                                                The tangents to conics request is ER# 1-1414911712

                                                 

                                                Go vote on them!