21 Replies Latest reply on Jun 17, 2014 4:41 PM by Jerry Steiger

    Modeling a coin - how to

    Nat Bajic

      Hello to everyone,
      I'm a CS student and never have worked in Solidworks until yesterday. As every powerful tool, it seems extremely complicated at first and I will definitely need to pass a few tutorials online along with a book I have before I can even think starting to do something.

       

      Anyway, within one of general computer graphics courses, I got an assignment to make a 3D model of a coin in SW. Of course I can't just download some model, I need to make it. Now, what I'm kindly asking is just to give me a few very general directions, what to watch for and steps that I'll need to do to make it from, say, a pic as a reference.

       

      Thanks!

        • Re: Modeling a coin - how to
          Chris Dordoni

          Hi Nat,

           

          This is an ambitious first project for learning SolidWorks.

           

          There are tools such as boundary surface and fill surface which you probably will use in creating the relief. However, the first step really is learning to use sketches (2d and 3d) which are needed to create surfaces. There are reasons to use a 2d sketch instead of a 3d sketch, or a 3d sketch instead of a 2d sketch.

           

          2D sketches let you use symmetry (or mirroring) and offsets which are lacking in the 3D sketches. 3D sketches can be moved in 3d space and are needed in creating complex surfaces. The spline curve points in 3d sketches can also be moved in 3d space.

           

          The first step is to draw the outlines of the features in a sketch based on your reference pic. I would use a 3d sketch for this.

           

          If you can post the pic that you are using, that would be helpful.

            • Re: Modeling a coin - how to
              Nat Bajic

              Thanks for prompt answer and explaining basic steps with sketches. Well, I wanted to make my local currency, http://www.hnz.hr/proizvod_opsirno.asp?pageID=250&pID=266

              My primary idea was to make a cylinder with small height. Reeded edge should not be a problem to make (I guess)

               

              Then, starting with simpler side for instance

               

              http://www.hnz.hr/upload/tbl_proizvodi/1kn-slavuj1993aversweb600px_85732.jpg

               

              I understand it might be fairly easy to model the letters as well. Is there any mask/selection using which I can lower down/raise selected part of the surface, it would make me half of the job. Relief in bird then remains. I think I would be able to draw the outlines easier then (didn't encounter that mask in tutorials yet, so sorry for asking stupid questions). If I fail completely, I would still be left with bird pic in 2D

               

              Also another question - how much would I complicate my life if I try to make the bird standing vertically on a horizontal coin? In 3D of course. Thanks.

                • Re: Modeling a coin - how to
                  Chris Dordoni

                  It is easy to extrude text for the lettering. Sometimes draft angle is an issue with very thin stokes, or very small text, but if you are doing this for an exercise, you may not be concerned with this.

                   

                  SolidWorks does not have a tool for masking and raising/lowering areas like in a poly modeler. The closest thing is the deform tool, and you can try it to see how it works. From my experience, deform gives you much less control than a similar method in a poly based modeling application. Polys and nurbs are very different and each have their strengths and weaknesses.

                   

                  I can show you how to use sketches and use the surfacing tools to make the relief later on today.

                    • Re: Modeling a coin - how to
                      Chris Dordoni

                      Here's something to get you started, its a version 2012, hopefully you can open that.

                       

                      You could probably model the head neck and body in one piece, if you put enough cross sections in it. For some things, it will be better to model as separate shapes (like the wings and legs) and join them together later.

                       

                      Also, in my example I used 2D sketches to trace the head, and 3D sketches to trace the body, just to show you can mix them for some functions.

                       

                      The cross sections in head and body are 3D sketches. You could use a 2D sketch for the cross sections, but you would have to define a sketch plane first and since they are at different angles, making these sketch planes could consume a lot of time if you have a lot of cross sections. So I find it more efficient to use 3D sketches since you don't need the plane defined.

                       

                      There's also capping the open ends and back side of the boundary surface to make it a solid (not shown). You might need to do for future operations. One thing at a time.

                      bird coin example.jpg

                        • Re: Modeling a coin - how to
                          Nat Bajic

                          WOW! Thank you so much for getting me started. I'll surely analyze it when I get my SW copy, I think versions at Uni are 2013 and now still waiting them for my copy approval.

                           

                          I'll eventualy be boring with other questions if I won't be able to figure out something by myself. Thanks again!

                            • Re: Modeling a coin - how to
                              Chris Dordoni

                              Sure, if you have any more questions post them here.

                                • Re: Modeling a coin - how to
                                  Nat Bajic

                                  Okay, done with edge, text on both sides, intrusion/extrusion and been playing with the boundary surfaces a bit since I wanted to learn about the features. Sometimes the program seems incredibly unintuitive although there is always a way around to solve it. Did not manage to find two things yet:
                                  1) this is something simple - how to lock and unlock the spline handles. When I create the spline they're facing oppositely on every point automatically and when I convert the text if I want to I need to do it manually. It's similar to smooth function in other programs,but smooth in SW does something else, I know.

                                   

                                  2) I'm clueless and feel stupid with this coat of arms that is like a checkboard. I want to extrude the grey fields with the sketch, but of course I get the error of intersecting lines. I can make all lines double and solve the problem but I'd really like to see if better solution is possible. Putting points on intersections does nothing I tries with splitting as well, still the same. Didn't find similar things online either. Any clues?

                                   


                                  CoA.jpg

                                   

                                  Thanks a lot once again!

                                    • Re: Modeling a coin - how to
                                      Chris Dordoni

                                      1) this is something simple - how to lock and unlock the spline handles. When I create the spline they're facing oppositely on every point automatically and when I convert the text if I want to I need to do it manually. It's similar to smooth function in other programs,but smooth in SW does something else, I know.

                                       

                                      You can change all the spline handles to "Tangent Driving", then the handles won't all move if you try to just one part of the curve. Select the dot at the tip of the arrow. There is no way to "break" the smooth handles to get a sharp point like in a 2d vector drawing program. If you want a sharp point, you will need to Split the spline at that point.

                                      spline grey handles.jpg

                                      spline blue handles.jpg

                                      split point 1.jpg

                                      split point 2.jpg

                                       

                                      I want to extrude the grey fields with the sketch, but of course I get the error of intersecting lines. I can make all lines double and solve the problem but I'd really like to see if better solution is possible. Putting points on intersections does nothing I tries with splitting as well, still the same. Didn't find similar things online either. Any clues?

                                       

                                      If you are using a 2D sketch, you can use the contours function. Any enclosed area can be extruded, just select the area. (If you are using a 3d sketch, you need a separate sketch for each object if they touch or intersect.)

                                      extruded checkerboard.jpg

                                       


                                        • Re: Modeling a coin - how to
                                          Nat Bajic

                                          Thank you. I didn't think of splitting the spline for such a simple thing.

                                           

                                          About the contours, after struggling with points and dots and deleting the extrude to start from the sketch again, it worked for a moment, actually it showed correctly how it should be, like on your pic, but upon accepting (pressing the green checkmark) showed me the "zero geometry" error. As I read about it I understand why it happens, but is there a way to solve it.I made sure to clear all the dots.

                                            • Re: Modeling a coin - how to
                                              Chris Dordoni

                                              I should have said to get rid of the single points. Glad you figured it out.

                                                • Re: Modeling a coin - how to
                                                  Nat Bajic

                                                  Actually I didn't figure it, it still shows the zero dimension error. I recreated the sketch as well, also works until I press the accept button.

                                                    • Re: Modeling a coin - how to
                                                      Chris Dordoni

                                                      Nat,

                                                       

                                                      If you are still having difficulty getting this to extrude, can you post your file?

                                                      • Re: Modeling a coin - how to
                                                        Jerry Steiger

                                                        Nat,

                                                         

                                                        SolidWorks won't extrude two rectangles that meet at one corner. You've got 16 of those corners where the thickness goes down to 0. Your only way out is change the corners to either have a tiny gap or a tiny overlap.

                                                         

                                                        Jerry S.

                                                          • Re: Modeling a coin - how to
                                                            Nat Bajic

                                                            Thanks Chris, I deleted it once again and recreated only the inner squares then extended the sketch. I think I confused program with something although simple selection of contour areas was all I done at the first place..

                                                             

                                                            I wanted to do as Jerry suggested but couldn't accept such a powerful tool like SW would not have a way to solve it smoothly. It's actually simple although it should be offered as help to choose contour areas when extruding instead of blocking all the features on extrusion

                                                              • Re: Modeling a coin - how to
                                                                Chris Dordoni

                                                                Here's a file that has 2 different extrudes. This only works with 2D sketches.

                                                                 

                                                                The first extrude has squares where the corner points touch. Using contour select works here.

                                                                concident points.jpg

                                                                The second extrude has lines that cross each other, so some of the squares don't have any corner points. Contour select works here too.

                                                                crossing lines.jpg

                                                                  • Re: Modeling a coin - how to
                                                                    Nat Bajic

                                                                    Yes I used the second, cool function.

                                                                     

                                                                    I'll dare to ask another question, this will be the last one since tomorrow is my deadline anyway. Today I've been working over 8 hours on 3D sketches and surface. Since I didn't manage to recreate the boundary surface (I tried everything as you drawed and selected in your example Chris) and not a single tutorial on youtube is very helpful, I tried with loft surface which is basically the same effect. I started with something as a leg of the bird just to get the feeling and I don't get this - if I use guide curves and if it doesn't fit anywhere near it, what's the use of the guide curves. I even added a thrid guide which was hard because of some reason it didn't wanted to accept it, showed two crossing lines between each other. I played with combinatins of the curves and then it worked. Crazy. Not even mentioning splitting the "pipe" in various direction should be normal for this feature but surely it does not work.

                                                                     


                                                                    loft.jpg
                                                                    Hard project indeed, I spent enormous time altogether and I got a feeling I didn't even catch the basics.   I attached the file so you can see what I was playing with.

                                                                    • Re: Modeling a coin - how to
                                                                      Jerry Steiger

                                                                      Chris and Nat,

                                                                       

                                                                      I was surprised that worked, so I had to try it out myself. The reason it works is because it generates a multi-body part. If you try to merge the squares with the body of the coin, SolidWorks won't allow it.

                                                                       

                                                                      Jerry S.