5 Replies Latest reply on May 19, 2016 10:50 AM by Jed Ferreras

    Automatic origin constraint

    Jed Ferreras


      I have been working with multiple cad applications and one of the most useful techniques I've ever learned was multi-body modeling. This technique allows users to export solid bodies as separate part files (derrived of  course) as well as an assembly (no constraints though, at least not within inventor and/or solidworks).



      What I would like to know is, do you know of or do you have a macro for adding origin to origin constraints for parts sharing the same origin or even better to use designated work planes to constrain parts to the assembly origin automatically.



      Specifically, my objective is to eliminate any relationships that may exist from part to part, this way any updates I add to the master model(s) would simply cause the entire assembly to update accordingly without the need to reconstrain.



      I have been able to pull this off quite easily within inventor, but in solidworks its not so straightforward.



      For instance,

      Inside inventor, I create a part file with sketches and workplanes that pretty much contain general design intent info (at least enough information to drive assembly, part locations, clearances, thicknesses, tolerances, as well as major features and even some critical component locations). Pretty much any information that would be critical to the design intent is included into a master file. However this file will generally have no features or parts or any solid modeling data whatsoever. Then I derrive this file into new part files where I use the pre-defined data to model new parts. Yes sometimes when i model a parts this way, some parts have to reference eachother. Once in the assembly however, I can go ahead and constrain the origins and whenever I make changes nothing gets messed up.



      Please review and advise.


        • Re: Automatic origin constraint
          Kevin Chisholm

          Not sure if this can help:


          Mate Macro

          • Re: Automatic origin constraint
            Deepak Gupta

            When you export multi bodies to assembly, all parts would be fixed and any change you make in parent model should get reflected to the assembly file. And bodies/part files should adjust. How adding mates would help?

              • Re: Automatic origin constraint
                Jed Ferreras


                First what I do is I make an empty part file.


                This part file has a first sketch with overall height and width. It also has a second sketch with overall depth. It then has a third sketch with overall design intent of the entire product (so imagine a water bottle, Id have a sketch with the shape and it'd be constrained to the other two sketches). Then there'd be a series of workplanes, some of which would require a sketch with a center point at some distance from a known centerline or something of that nature (some critical location geometrically speaking).


                Once this empty part file is complete, I insert it into every part that I will make or use in my assembly. Sometimes the new parts have to be multibody. But even when i have multibody, I am still working with sheet metal and need to generate flats. I also need to check tolerances and clearances, sometimes I have to do configurations, therefore I need the assembly. Most important of all, is the drawing, which the fabricatiors need, so yeah the multibody model is just a step in the process, I still need drawings.

                  • Re: Automatic origin constraint
                    Deepak Gupta

                    You can do drawings for multi bodies also and there can be one body per sheet or one drawing per body.


                    Also I would rather create a layout in assembly mode OR would insert the master file in assembly and take references there instead of inserting part into every single part.

                      • Re: Automatic origin constraint
                        Jed Ferreras

                        Again i am working with sheet metal, also I am working in a team not on my own, also we have part numbers for each part.


                        I dont agree with making references inside the assembly, this typically results in alot of issues and broken constraints once changes start to flow in.


                        Ideally the goal would be to have a single point of entry for all and any changes, one file where all the parts follow from it.