18 Replies Latest reply on Sep 24, 2013 12:37 PM by Nick Grisco

    Working with bone

    Murat Ali

      Hello all,

       

      I would really appreciate some suggestions on working with bone, I have a solid bone model (in both IGES and STEP) format. I am trying to "shell" the bone and "thicken" it by 2mm. I have tried a number of options including:

      - shell and thicken

      - offset

      - cuting the bone in half and deleting the end face, kniting the surfaces and then thickening

       

      I am trying to split the model into two parts,

      1) The first 2mm depth of bone from the surface to be one cortical bone (material property)

      2) The internal material of the bone to be cancellous bone (material property)

       

      Everything I try does not to work succesfully, I would appreciate some input from others.

       

      I have uploaded a few versions of the bone to dropbox (and also attached them below to this post) if anyone can help, thanks. I look forward to your suggestions.

       

      Full model (STEP file) http://dl.dropbox.com/u/32683816/bones/User%20Library-Human%20Femur.step

      Full model (IGES file) http://dl.dropbox.com/u/32683816/bones/User%20Library-Human%20Femur.igs

      Shell model (Soldworks) http://dl.dropbox.com/u/32683816/bones/Femur_1.SLDPRT

        • Re: Working with bone
          Alan Stoldt

          Murat,

           

          Can you "dumb" down some of the geometry on the bone (joint) ends? The undercuts are causing the offsets not to work, if they were simplified you might bwe able to get what you need.

           

          I was able to do a surface offset of 0.0 only, so have the shelled out shape, no thickness.

           

          Good luck,

           

          Regards,

           

          Alan

            • Re: Working with bone
              Murat Ali

              Hi Alan,

               

              Thanks for your input, I guess I could simplify it, but wanted to see if I could work with the original bone. I too could get much further than what you have achieved with this.

               

              I wonder if there is some "Auto smoothing" feature to help with this. I am just thinking about process automation.

               

              Thanks for trying and providing help with this.

               

              Murat

            • Re: Working with bone
              Alin Vargatu

              Are you thickening outward or inward?

              • Re: Working with bone
                Alin Vargatu

                Too bad we do not have this handy diagnosis tool in the offset command UI.

                 

                Shell Diagnosis.jpg

                  • Re: Working with bone
                    Murat Ali

                    I try to thicken both ways, it processes for about 5 mins and then nothing happens (like I never pressed the tick button), at this point I do not recieve any error messages.

                     

                    How did you pull the diagnositcs section I couldn't see that in my shelling options.

                     

                    Any further advice on this would be much appreciated, or any other software packages that might help?

                     

                    Thanks.

                  • Re: Working with bone
                    Alin Vargatu

                    See attached. Sorry for the delay. We wrote a program that identifies all the faces that cannot be offsetted and offsets all the faces that can be.

                     

                    femur.jpg

                     

                    femur 1.jpg

                      • Re: Working with bone
                        Murat Ali

                        Hi Alin,

                        It seems that SolidWorks already picks up the surfaces which can not be offset, what advanatages does the program your wrote offer. Also, is there any solution to actually helping to offset the surfaces which can not be offset? Thanks for your response it is much appreciated.

                        P.S. What is the code? Is it a macro? Are you able to share this?

                        Many Thanks.

                          • Re: Working with bone
                            Alin Vargatu

                            Hello Murat,

                             

                            I was not aware that SolidWorks can identify the surfaces that could not be offset, other than by using the Shell workaround; and even that is quite cumbersome.

                             

                            In regards to our little routine, at this time our programmers are performing final testing. I'll let you know when they finalize it.

                            I understand your interest, because I had needed such functionality for a long time myself.

                            • Re: Working with bone
                              Alin Vargatu

                              Sorry Murat, I was trying to upload the modified SW files, but I at this time I cannot upload anything other than pictures to this forum. I will try again tomorrow.

                            • Re: Working with bone
                              Nick Grisco

                              A little off topic, but would you be willing to share that program you wrote? It's always a pain when offsetting a large group of surfaces only to have it fail when one won't offset, but you don't know which one it is. Then you have the time consuming task of going through each one to find the problem surface. So if you'd be willing to share, that'd be awesome! If not, I understand that you can't just give away all your hard work! :-) Thanks!

                               

                              ~Nick