7 Replies Latest reply on Jun 14, 2013 12:11 PM by Andrew Brown

    180 degree panic

    Dylan Scoles

      Does anyone know why solidworks would automatically add 180 degrees to the angles I tell an arc to be?

      It seems to hapen every time I try to set an arc angle- if I set it to 20 degrees, it becomes 200, if I set it to 80, it becomes 260. I can get it to angle I need if I type it in again, but I don't see why solidworks would change angles automatically like this. It's been getting really annoying when it merges endpoints 180 degrees away from where i wanted the arc to end, and i need to delete the line and work around about 5 steps to eventually get it to where I need it.

      Is this just a glitch, or is there an option somewhere to turn this off? If this is an intended feature, what is its purpose?

      SW 2007 student
        • 180 degree panic
          Kelvin Lamport
          How are you setting the angle?

          Can you post a screen shot?
          • 180 degree panic
            Anna Wood
            Post a screen shot or your model with an offending sketch in it.

            I suspect it is your selection process. Hard to tell without watching over your shoulder.

            Zip your files before uploading.

              • 180 degree panic
                Dylan Scoles

                I'm setting my angles like so:
                Drawing a center-point arc at a random point, then selecting it to define the angle by typing it in the angle defining box. Also by defining the angle of any pre-existing, otherwise constrained arc by typing in the angle defining box. It seems to be about 1/3rd of the time 180 gets added to the angle.

                These screenshots show my input and the output arc- #1 shows how it's been wreaking havoc with my sketches, #2 shows a plain arc.

                thanks for your help
                  • 180 degree panic
                    Matt Lombard
                    I know you didn't ask, but...

                    SolidWorks sketcher has a terrible time with tangent arcs. You're WAY better off if you sketch the feature you show in the images as a thin feature (single loop, no offsets), and apply fillet features to the solid rather than what appears to be an AutoCAD-esque approach of literally sketching every little thing. If I were doing this, that's probably what I would do. Sketch fillets are so tempting, but in SW it's just not worth it. Use fillet features instead. Plus, when/if the fillet features fail, they don't take the entire feature down with them.

                    Plus, if I'm not mistaken, it looks like you're using the PropertyManager to apply angles. In SW we generally do things like that with dimensions on the geometry. If you don't use a dimension or sketch relation, it isn't constrained. The PropertyManager is supposed to be a valid way to edit sketches, but I only use it when there are no other options.
                • 180 degree panic
                  Kevin De Smet
                  In SolidWorks' defence, it can actually be quite satisfying seeing a very angular shape "transform" into a beautiful model - with just a few clicks of the mouse, using the fillet features.. Could just be me though!
                  • 180 degree panic
                    Josh Brady
                    I can't echo Matt's last paragraph loudly enough. I've been using SW for about 5 years now, and I've never had occasion to try to edit entity parameters directly as you're doing. Using dimensions and relations to constrain entities is the whole point of parametric CAD. With non-parametric, you put the lines and arcs where you want them and then add dimensions that "describe" what you did. With parametric, you rough in the lines and arcs and add dimensions/relations to "tell" them where they should be, based on your design intent. Changing entity parameters directly is sort of like driving your car in reverse. You might have to do it sometimes, but it goes much slower. And if you do it too long it's a pain in the neck.
                    • Re: 180 degree panic
                      Andrew Brown

                      Nice to see that even in SW 2012 SP5 this is STILL an issue.  Trying to set two arcs to 18 degrees, and every single time it'll replace my 18 deg with 198.  Even clicking on the +/- arrows on the property manager immediately adds 180 degress to the angle.