10 Replies Latest reply on May 25, 2012 7:30 AM by Eugeny Kalashnikov

    Stuck at surfacing

    Eugeny Kalashnikov

      Hello folks, I am a student in Industrial Product Design, at the moment I'm modelling a hunting knife in Solidworks

       

      I made a real size model out of ploystyrene foam. Now I've done pretty wel in reconstructing all the surfaces (using the loft command), but I really got stuck at that curve where my thumb is supposed to fit...I haven't really had a course at freeforming yet so I'm trying to find my way with lofts and sweeps, cut extrudes and other basic comannds. If any of you have suggestions on how to fix it, they will be very, very welcome!

       

       

       

      I will include some pictures to help visualise the situation.

      http://i155.photobucket.com/albums/s311/Yev300/401643_4015943523114_1417112814_33517751_1460779339_n.jpg

       

       

       

      http://i155.photobucket.com/albums/s311/Yev300/Kalashnikov_Eugeny_Handen_Jagersmes.jpg

       

       

      Thanks for your time!

        • Re: Stuck at surfacing
          Jeff Mowry

          Those are tricky.  Can you post the file?  Which version are you using (v2011, v2012)?

           

          Seeing where you are now, consider using split lines to remove the areas of this surface that do not create the scalloped surface, then set up some surfaces to form a Fill or Loft for your inner surface, then loft your thin crescent-shaped surface from the edge of your new scalloped surface to the edge of your split-line-removed handle surface.

           

          If you post the file, I can show you how to do this a bit better in the model.

            • Re: Stuck at surfacing
              Eugeny Kalashnikov

              I use the solidworks 2011 student version.

               

              I added the file to the original post, sorry it is quite sloppy and undefined. I only want a quick 3D model for some renders I have to use on my presentation poster. Thanks for looking into it!

                • Re: Stuck at surfacing
                  Jeff Mowry

                  OK, below are some snapshots of what I meant--also a bit quick/sloppy, but it should illustrate the point.

                   

                  screenshot3482.jpg

                   

                  screenshot3483.jpg

                   

                  screenshot3484.jpg

                  There were some geometry issues on the front/top curve of your handle.  Normally when modeling a symmetric part like this, it's more efficient to model only the half/quarter/whatever that you need, and then pattern/mirror the surface/solid bodies to get the whole part back.  So the first thing I did with your model is cut it in half.  But when I did so, the front/top curve of your handle didn't fully convert entities into my sketch.  So something seems a bit amiss there.

                   

                  I created your scalloped area in surfaces, but the knit failed to merge the surfaces back into a single whole.  The blue lines in the snapshots are "open" edges in the surface bodies where the edges failed to knit to their surrounding surfaces during the knit command.  Normally these would knit properly, I'd mirror the surface body, then knit again with the "form solid" option to return the part to a solid.  As it is, it's only a surface model.  But this should illustrate the concept of how to model this sort of feature.

                    • Re: Stuck at surfacing
                      Eugeny Kalashnikov

                      That is simply magnificent!

                       

                       

                       

                      It's not quite what I had in mind, as my model was assymetric and only to be used by right-handed people, but doing it the way you do I might make my product in a way to be used by everyone. I thank you for your small tutorial, I will tweak my model a bit more, and if you wish I could show you the result soon

                       

                      Thanks again!

                        • Re: Stuck at surfacing
                          Jeff Mowry

                          Sure, no problem.

                           

                          If you like, show all the surfaces in the surface bodies folder, then roll back to where I started making tweaks.  You'll see all the construction surfaces needed to create what you want this way.

                           

                          I'm eager to see how this turns out.  I do a lot of handle design myself--lots of hand tools and related things.  There are pros and cons on ambidextrous designs, but they're certainly more universal.

                            • Re: Stuck at surfacing
                              Eugeny Kalashnikov

                              Great, I will do that !

                               

                               

                               

                              How do you, as a professional handle desginer, like my knife handle though?

                                • Re: Stuck at surfacing
                                  Jeff Mowry

                                  Are you sure you want my opinion on that?   

                                   

                                  To me, it looks a little difficult to maintain a good/safe grip.  How does the foam model feel?  What are the materials?  I go a lot by "feel", keeping in mind this varies greatly depending on the size of the user's hand.

                                   

                                  I start with a malleable material (like clay) when designing handles, since many handles require slightly different gripping techniques, depending on what you're doing with the tool attached to the handle.  By doing this, I can put impressions or bulbs where they fit best.  The form or design follows function this way.  From there, I figure out how to get that shape represented in CAD, which can be a pain.  But the end result is that--if I've captured what I made in clay in CAD properly--the handle works well.  Starting with sketches makes little sense to me, since the effectiveness of the handle is determined by its shape.  And it's tough to shape the handle properly without feeling it and actively shaping it as you go.

                                    • Re: Stuck at surfacing
                                      Eugeny Kalashnikov

                                      The foam model feels okay, but not too comfortable. Well I don't really know any other solutions than this, and I'm out of time because tuesday is the deadline :/

                                       

                                      I do apreciate your opinion though

                                       

                                      I tried to design the grip using the shape characteristics we had developped in a group of 3 students (see attachment)

                                        • Re: Stuck at surfacing
                                          Jeff Mowry

                                          Don't take what I say as discouragement.  You asked someone who does this for a living, sometimes gets awards doing so, and uses SolidWorks to express everything in 3D.  That's bold.  You're in school, you learn as you go, and apparently had to fit this in with a design-by-committee sort of thing (something I have difficulty doing).  Judging by the mood board, this project is about more than a final outcome in 3D CAD--more of a whole design-effort approach.

                                           

                                          Most industrial designers start with sketches in design.  Much of the time, that's a great place to start.  With handles/grips/human-interface, I find that rarely to be the case.  This is one area where "feel" often trumps design/aesthetic, so starting with a medium that allows you to check "feel" is generally a better place to start.  If you look at my designs, you see they're quite utilitarian.  I do a lot of hand tools, medical stuff, etc.  I don't do "ornamentation" very well, so you don't see a lot of surface styling or other imagery that doesn't directly serve the function of the product with my stuff.  That's a weakness in some industries and a strength in others.  As you move through school and begin working on "professional" projects, you'll find a niche you enjoy and will likely be quite different from my own.  I've got a lot of experience with plastics, so I tend to work in areas where plastics do their best (swoopy shapes, human interfaces, etc.).

                                           

                                          So--please don't take a little critique from a crusty industrial designer as discouragement, but use the comments to your advantage.  We used to have pros come in and critique our work (when I was a student at ASU) quite regularly, and it seemed it was nothing but negative comments.  However, those of us who listened and understood what they were saying got a lot of free advice that was a nice gift.

                                           

                                          Keep up the good work.  We didn't even have any sort of CAD system at all in our design department when I was in school, which was a distinct disadvantage when entering the work-force.  Good to see you've got access to SolidWorks.

                                            • Re: Stuck at surfacing
                                              Eugeny Kalashnikov

                                              Yes I understand, you did quite the countrary of discouraging actually! You motivated me to use shapes more often than sketches and I will keep that in mind next time I'm about to design a shape to be used by human hand.

                                               

                                               

                                               

                                              Your advice has been better than the one of my tutors over the 2 years of studying of product design and I'm glad you have given me some.