19 Replies Latest reply on Sep 22, 2012 7:29 PM by Rick McWilliams

    When surfaces are a solid but not a solid.

    Richard Gergely

      It would appear in surfacing if the final surface produced also knits together within that feature (certain types of trim for example) and it was the only/final gap as such in the surfacing it results in a fully knitted model. This model has no gaps but is listed as a surface entity. As all the surfaces are knitted together there would appear to be no function in solidworks to convert this to a solid (or rather SW just to recognise it as a solid which it is).

       

      I know the work around - make sure the last feature while surfacing doesn't knit/or off set a surface zero and delete the original and knit to solid. Which either is all a bit a of a mess around.

       

      So am I missing something really simple here which makes SW know that it is now really a solid??

        • Re: When surfaces are a solid but not a solid.
          Bill Tucker

          Richard

           

                        My experiance has been it remains a surface face until it is thickened. Try adding a marginal thickness.

           

                        Bill

          • Re: When surfaces are a solid but not a solid.
            Jeremy Feist

            insert->Boss/Base->Thicken. make sure the "create solid from enclosed volume" is checked.

            • Re: When surfaces are a solid but not a solid.
              Alin Vargatu

              Richard, it is quite easy to check for gaps or rips in the surface body (you need to eliminate gaps and rips before thickening).

               

              Just use the Check tool (using the selected items option if you have multiple surface bodies):

               

              http://help.solidworks.com/2013/English/SolidWorks/sldworks/HIDD_CHECK_ENTITY.htm?id=e55c6f6a6ae043a183afbe46312585b8#Pg0

               

              It will identify the open edges, if there are any. Stitch those open edges, or close the gaps.

              Once that is done, you can use the Thicken command to turn the surface body into a solid.

               

              check.jpg

               

              As a side note, the Knit command allows you to skip the thicken step, if the resulting surface encloses a volume.

               

              knit.jpg

                • Re: When surfaces are a solid but not a solid.
                  Richard Gergely

                  2 notes here. Firstly I don't want to thicken and second there is no gaps or imperfections in the surfaces.

                   

                  Simply by making sure there is a surface which needs to be knitted at the end gets rid of the problem because you have the option to make a solid.

                   

                  So Alin have a play around with trim with the mutul trim option and see how it will knit everything together  - leaving you with yes a solid but it's not a solid. This is not the only surfacing feature which has the same outcome.

                    • Re: When surfaces are a solid but not a solid.
                      Jeremy Feist

                      Firstly I don't want to thicken

                      that is like saying "I don't want to seal the grout on the tile I just installed." currently it is just part of the process. if you want to change the process, submit ERs to include the "try to form a solid" check box to all of the surfacing commands.

                        • Re: When surfaces are a solid but not a solid.
                          Richard Gergely

                          Why would I want to thicken anything on a imported automotive model for instance that just needs repairing. It may have gaps, it may have bad surfaces, it may have tiny surfaces not needed, it may have over lapping surfaces, etc. But I can't see why I would need thicken???????

                           

                          All what should be needed is once you sort the surfacing out you either knit into a solid or the command that has knitted all the surfaces together should accept it's a solid or at the very least give you the option.

                            • Re: When surfaces are a solid but not a solid.
                              Alin Vargatu

                              Richard Gergely wrote:

                               

                              Why would I want to thicken anything on a imported automotive model for instance that just needs repairing. It may have gaps, it may have bad surfaces, it may have tiny surfaces not needed, it may have over lapping surfaces, etc. But I can't see why I would need thicken???????

                               

                              All what should be needed is once you sort the surfacing out you either knit into a solid or the command that has knitted all the surfaces together should accept it's a solid or at the very least give you the option.

                               

                              Hmmm, maybe because the Thicken command will just turn the manifold surface into a solid?

                               

                              thicken.jpg

                          • Re: When surfaces are a solid but not a solid.
                            Alin Vargatu

                            Aha, you are right and I agree. The mutual trim should get an option for turning a manifold surface into a solid.

                             

                            I suggest you submit an ER on this topic.

                            • Re: When surfaces are a solid but not a solid.
                              Dwight Livingston

                              Richard Gergely wrote:


                              As all the surfaces are knitted together there would appear to be no function in solidworks to convert this to a solid (or rather SW just to recognise it as a solid which it is).

                              Firstly I don't want to thicken and second there is no gaps or imperfections in the surfaces.

                              Richard

                               

                              I not sure even Alin's post was quite clear enough. The "Thicken / Create solid from enclosed volume" is exaclty the function you said you wanted. Yes, it has a terrible name that makes it impossible to discover. Took me a long time to undrestand that and actullay use it. A function called "thicken" should not be used to make a solid without any thickening going on, no more than an "Offset" function should be used to copy a surface. And no one should have to look in the "Insert" menu to delete a face. But that's what we have.

                               

                              Dwight

                               

                              Edit: I see you answered before I did, and seem to understand the deal. Sorry to repeat. I do think an improvement could be made if, in the "Thicken" function, you could pick more than one surface body and both knit and make solid.

                          • Re: When surfaces are a solid but not a solid.
                            Roland Schwarz

                            One of the first things to get over in surface modelling is the length of the feature tree.  Adding a feature to take a surface to solid is no big deal usually next to nothing in terms of burden on rebuild times.

                              • Re: When surfaces are a solid but not a solid.
                                Richard Gergely

                                You can look at it that way I suppose but really we should try and make the software better. Other CAD systems don't have this problem and in ease of making changes to SW to eliminate it it should be fairly easy.

                                 

                                It falls into the same band as having to offset a surface zero and delete the existing surface = a bit carzy. You can do this but really unknit surface makes sense and reduces history

                                  • Re: When surfaces are a solid but not a solid.
                                    Roland Schwarz

                                    True dat.

                                     

                                    However, surface modelling is also about much more than making swoopy shapes.  It's also about taking "manual control" over things that solid features do automatically.  Now the user is deciding if/when/how faces get trimmed and united.  That also means sometimes having to explicitly dictate things that may seem "automatic".

                                      • Re: When surfaces are a solid but not a solid.
                                        Richard Gergely

                                        You see I see it exactly the oppsite. SW has enough surfacing functions to get you by but it's not it's forte. It's improved much over the years.

                                         

                                        What you are saying in actual fact SW is doing exactly the opposite. It's not allowing you to decide when and how.

                                          • Re: When surfaces are a solid but not a solid.
                                            Jerry Steiger

                                            Richard,

                                             

                                            To tell you the truth, I don't see this as beeing a big deal. I didn't think it was much of an improvement when they added the check box on Knit Surface, so we didn't have to add a Thicken. So put in an enhancement request and join the others waiting in line. Personally, I would much rather see Mutual Trims that are less likely to break when I roll above them in the tree and modify something.

                                             

                                            My apologies if this comes across sounding snotty. My brain is a bit fried from a long day flying yesterday and a short sleep last night.

                                             

                                            Jerry Steiger

                                             

                                            Message was edited by: Jerry Steiger

                                              • Re: When surfaces are a solid but not a solid.
                                                Richard Gergely

                                                Jerry

                                                 

                                                Yes got the enhancement request in. It's always going to be much similar with with any problem. It depends what you do, how often you see a problem, have you been used to not seeing such a problem perhaps in a previous CAD package. So it's very subjective the importantance of a problem to one person to another. What I see as a problem someone else won't.

                                                 

                                                TBH my experience of mutal trims loosing there function is a come problem in any history based system. It is pretty annoying but I think it is problem with several other features such as split and anything that selects multi surfaces that might loose association with specific selections. Some features seem to have a better hit rate of maintaining what they were supposed to do but certainly mututal trim does stand out as one of the most likely to fail first. I have a feeling it is a hard thing to fix and of course you have got to expect if you change things before it in the history enough there is a point it is impossible for a feature to pick the correct what ever

                                      • Re: When surfaces are a solid but not a solid.
                                        Rick McWilliams

                                        I have found that mutual trims are one of the less stable forms of trim surface. Beware that these may break spontaneously.