6 Replies Latest reply on Apr 6, 2016 2:31 PM by Ben D.

    How to "flat pattern" section view of solid with an arc?

    Ben D.

      I want to make a section view of a solid (or sometimes the assembly) which is an arc shape. I am interested in "theoretical" flattened view - linear lengths etc. I am trying to section with an arc, but receive an error:



      The sectioning sketch is an arc with two lines at ends. This is a simple extrude (it is for this example, but in reality I have assemblies - so I can not use sheet metal flat pattern as a workaround)


      On the other hand, it seems that an arc is allowed to section the view. This is another example:


      This is also a sectioning with arc+2lines, and seems to be working fine



      I have tried to section with arc in some different situations during time with different SW versions, and never understood what was the limitation that was giving error like in the first picture, or any other misbehavior that I can not remember now


      So, it is possible to section an "arc-shaped-model" with the arc? If so, then how?


      Thank you for your help

        • Re: How to "flat pattern" section view of solid with an arc?
          Ben D.

          I have read some more information about section view, and it appears that an arc I used in the second image is used as an "offset", and not as a cutting line. In other words, the section view on that second image - is formed by the dashed horizontal line, then interrupted at the end of it, material is excluded from the section view throughout the arc (which is solid line in the screenshot) and then the section view is continued with an angled line (again dashed). This is performed automatically by solidworks: the sectioning sketch is changed (an arc is changed to construction geometry, and the straight lines are not).


          Interesting thing is that in sketch environment solid lines are solid, and an arc (which is construction geometry) - is dashed, but when you exit the sketch - it "inverses" - it shows section lines in dashed, and an arc (which is an offset) - in solid line


          Anyhow, the question remains - is it possible to actually section the material with an arc?

          • Re: How to "flat pattern" section view of solid with an arc?
            Mike Helsinger

            It looks to me like you are taking an unusual approach to getting the flat length.  There are a couple thoughts that come to mind.


            In my mind the approach you are describing is the work around.  Sheet metal technique will give you the flat length regardless of this part being created as an extrusion or a piece of an assembly.  I recommend you use the sheet metal tools rather than extrusion to model this kind of part, or Convert to Sheet Metal on the model you have.  Is there another limitation to making this a sheet metal flat pattern?



            Going the route you illustrate, you can use some different tools and still get there.  Rather than creating a section view, use line & arc sketch you have created and use the path length dimension to find the linear measurement you are going for.


            The path length dimension takes the total length of multiple sketch entities.  You will need to start your sketch outside the bounds of the part view and use more than one sketch element, it will not take a single element as a valid entry.  In my view I used two coradial arcs with ends at the midpoints of the part edges.  Your line-arc-line sketch may do the trick if you set it up right.  You can even use the k factor as a ratio of the inside / total length of the edge in lieu of midpoints to locate your arc and generate the true theoretical flat length this way.

              • Re: How to "flat pattern" section view of solid with an arc?
                Ben D.

                Mike, thank you for your input


                As I said, the first image represents only the idea of what I need. In reality, I need to section the assembly - e.g. curve conveyor with chains, attachments, and other machinery. I am not talking about a single part.


                The dimensions are only one of the reasons. It would be also useful to see the "flattened" view for kinematics between two points and so on.


                So again, I want to section an arc-shaped assembly, is it possible?

              • Re: How to "flat pattern" section view of solid with an arc?
                Anna Wood

                I was able to cut a section by extending the rad past the part then creating two tangent straight lines....    But nothing shows up in the section view.


                I think this is a limitation in SolidWorks.



                  • Re: How to "flat pattern" section view of solid with an arc?
                    Mike Helsinger

                    It seems that you are finding the limits of the tools we have available.  Perhaps you could take a method that includes all of the above?  It seems like you can't quite create the section view that you can't quite create.  If that's the image you need to put on a drawing perhaps you can cheat get creative?


                    The following would be a stretch of proper technique so proceed with caution.  If your actual assemblies are relatively simple as these examples then you might create the section view that doesn't quite show what you need, or shows nothing at all.  Then double over it with your own sketch that looks like the view you want to create, and dimension it as needed.  You can take the path length to get your numbers and just make your sketch match that.  You'll just need to take a careful look at all your details as it seems whatever you do you are differing from the model.  It will look like the view you need to show, and you checked and double checked your illustration so problem solved?  I hope?


                    This may not be practical for what you are actually working with.  If it works it could be a bit tedious and it's nothing close to perfect but if you really need to put this view on a print you may just have to get creative.  Or perhaps you could scrap the view and annotate the information you need to convey somehow.  I hope something here is useful to you.