4 Replies Latest reply on Jul 17, 2013 3:24 AM by Jared Conway

    How to split emissivity values on one object

    Richard Kodama

      I have a part for a thermal study.  It has a planar face that should have two different emissivity values.  One emissivity should be assigned to an array of small spots, and the remaining area should be the other emissivity.  I guess I should start with a sketch of the spots.  There is a "split" tab in the "Radiation" dialog box, but I can't seem to get it to work.  Is this possible?  I suppose I could create plugs of material under the spots that are bonded to the rest, but I think this would be very time consuming to set up, especially given the large number of spots.

       

      Thanks,
      Richard

        • Re: How to split emissivity values on one object
          Jared Conway

          the split tab is just a window into the split curve function. you'd have to do each spot individually. my trick is if you create a sketch of the spot circles, extend them as a surface body, use insert > curve > split line > intersection you can do multiples at one time. i think there was a trick to do this with a projected sketch but i forget what it was. then delete the surface bodies and you're good to go.

           

          plugs or multibodies would work too. just be careful how many faces you make. they all add to the computation time.

            • Re: How to split emissivity values on one object
              Richard Kodama

              Thanks.  I am able to create the split during part editing rather than using the split tab.  However, the only way I see to select those regions is one by one.  Is there a way to multi-select all the "splitted" regions?  Can I group them after selecting?  I tried to multi-select by drawing a rectangle, but it only selects the outlines rather than the surface regions.  In some cases I might have a few hundred features, so I hope there is a way.

               


              I'm not familiar with surface bodies but I will look into it if it would help.

                • Re: How to split emissivity values on one object
                  Jared Conway

                  You can try a selection filter for faces to select them. If that doesn't work, you might be stuck. After creating the selection, there is no way to group them for the future. Both are great enhancements to submit through the SolidWorks Customer Portal.

                   

                  Something to consider, do you think creating individual surfaces for each is really necessary? Could you create a split for the overall region and then determine some overall emissivity for that region based on the area ratio of the 2 emissivities? From a calculation perspective and setup perspective this is going to be a lot easier.

                   

                  The surface body method is just for creating the split lines. Probably won't help you if you were able to select them.

                   

                  Another thing I just thought about, if you connected each region with a small "spar" sketch between them the split would be one big face that you could select in one shot. This will add some mesh complexities and will add some emissivities that are different than you want, but would help your setup.

              • Re: How to split emissivity values on one object
                Shaun Densberger

                Hmm, not sure why the split tab isn't working. Did you try to manually create the split in the CAD part of SW?