6 Replies Latest reply on Mar 18, 2011 11:41 AM by Charles Culp

    IGES Surface issues

    George Maddever

      Hi All,

       

      I'm currently working with a client who designs surfboards in MaxSurf. He exports the geometry to me in IGES format and then I use this to form it into a solid and add some internal geometry.

       

      He has a catalogue of boards of different shapes and sizes and they seem to import and build with varying degrees of success. Typically the boards have three surfaces, a base (the bottom of the board), the deck (the top of the board) and the rail (the surface around the board periphery that links the two.

       

      The base and rail surfaces almost always build fine and are easily convertable into usable geometry, however, the deck surfaces are much more problematic.

       

      I've identified some artefacts in the way the decks are modelled with him that's causing some issues, and we're working together to rectify these, however some of the surfaces that should be usable just don't seem to be for some reason.

       

      In the attached model, there's a very small flaw in the deck near the nose of the board that trips things up, and the surface at the tail of the board runs down to a singularity which is never a good thing.

       

      I have managed to convert some of these models to usable geometry by cutting off the nose and tail of these surfaces and blending in filled surfaces to remove flaws and singularities, but then trying to thicken or offset these surfaces, I'm still getting errors. I've run the check function and there aren't any tiny radii there that I can see, am I missing anything else?

       

      Are there any simple fixes I'm missing here? I've got a whole catalogue of these to go through and work with, so I'd like some simple suggestions in how to turn the board surface IGES models into usable solid geometry quickly. If I spend a day on each board model, I'm sure I can make them good, but I think that'll blow the project budget out of the water. Ideally I'd like to write a macro to automate the process once I find how to make them good.

       

      The client is also re-doing a lot of their surface modelling so I'm hoping to give him some feedback on how to better build his surfaces to integrate with SolidWorks if possible... so any advice on that front would be good too.

       

      I've attached a sample IGES file if anyone wants to have a play.

       

      Thanks in advance,

       

      George.

        • Re: IGES Surface issues
          Kevin De Smet

          I notice a crease near one of the ends of the model, I suspect this is from the .iges or source, you shouldn't have to fix things that pervasive if you intend to have models sent to you on a regular basis, it's costly rework that's just complication.

           

          Before trying more invasive things try to ask for a STEP file, it's the successor to IGES and should be better more often than not. Also, if the surfaces can be defined as a watertight collection in the surfacing application so it recognizes the model makes an enclosed b-rep, that might improve your chances of getting a successful import.

           

          The best way to bring an IGES file successfully into Solidworks, is to use STEP

          • Re: IGES Surface issues
            Geoffrey Leonard

            Hi George.  As a standard we accept .x_t and .x_b files. The surfaces converts perfectly into SolidWorks. STEP is also not a bad format to use. We only use iges for our CNC Programmers.

            • Re: IGES Surface issues
              Thomas Idebrant

              Hi George!

              I'm not exactly sure what you are looking for.

              But I believe that you wan't the surface model to be a solid or a shell without errors.

              I did that with the sample model you provided. It was not a big deal to make it happen. I'll try to explain with the pictures.

               

              I did open your model and trimmed the surfaces in two steps.

              1 trim 1.jpg

               

              2 trim 2.jpg

               

              After that I knitted the surfaces.

              3 knit 1.jpg

               

              And so...there it is. Both as solid and as a shell.

              4 solid 1.jpg

              6 shell 1.jpg

              As I said. I don't know if this is it...

              Good Luck!

              Thomas

              • Re: IGES Surface issues
                Keith Parker

                Hi George

                 

                Unfortunately there are lots of issues with those surfaces.  In addition to the others' (especially Kevin's) comments, have a look at the attached zebra-striped images.  Looks like the two halves of the original surfaces are neither tangent nor curvature continuous.  This is the discontinuity in the surfaces that's giving you that top-surface centreline crease towards the front of the board.  Also there's no tangency or continuity from the upper surface to the rail surface.  A quick zebra-stripe of the two bottom surfaces also shows clear discontinuity along the centreline.

                 

                Unfortunately your client has to up his game & give you better surfaces.

                • Re: IGES Surface issues
                  Charles Culp

                  1. That point near the nose looks like a translation error. Getting a higher quality export might fix that (export settings on their end).

                   

                  2. Other than that, yeah, I don't know of any easy solution. I played around with this for a while, and without knowing which is "correct" I wouldn't know how to attack this. Is the base or the rail the correct geometry?