10 Replies Latest reply on Aug 13, 2018 1:17 PM by John Stoltzfus

    "Sketch contains dimensions or relations that no longer exist"

    Matthew Robertson

      Hello everyone, I'm working on a prototype part that I'm making lots of little adjustments on as I test out different shapes and features to see how they might work. It's a pretty simple piece just using a couple extruded sketches and cuts, but since I'm constantly making changes I keep getting error messages from features further down the tree from sketches saying they are missing dimensions or relations when I make changes to the first feature sketch. Initially I thought it was because I was sometimes using a face on the part to make a sketch plane that I would then use for another feature, but after using nothing but the origin planes for my sketches and still getting the error I'm not really sure how to prevent it from happening, or how to quickly fix the issue besides deleting the feature and redrawing it.

       

      Thanks!

        • Re: "Sketch contains dimensions or relations that no longer exist"
          Dave Bear

          Hi Matthew,

          If I am understanding you correctly, you are telling us that you are creating a solid and then modifying step by step sometimes by editing previous (or the initial) sketches. If this is the case, then what you need to realise is that as you proceed with your model your features are dependent on the sketches that you create. If you then go back up the feature up the feature tree and edit a sketch you may be removing some of the elements that the features lower on the tree are relying on, hence the errors. I don't know how much knowledge or experience you have with SolidWorks and I'm sorry if this sounds condescending but it is pretty basic stuff. Of course, my comments are based on my interpretation of your question.

           

          If you can attach you model then forum members can clearly see where the issue may be and help you resolve the issue.

           

          Dave.

          • Re: "Sketch contains dimensions or relations that no longer exist"
            Ian Moore

            You're likely referencing edge or guide lines in your sketches in ways that the relationships gets lost as you alter your feature tree. It takes a little practice to know when/how this will happen, but in general it's just modeling habits that can correct it. Any of the sketch relations in your sketch (coincident, parallel, concentric, etc.) that are related to some edge (or boundary line) on your model and not just the sketch have the potential to do this.

             

            So, the first thing is to try to relate to your sketches to your bodies/surfaces as infrequently as possible.

             

            Here's a rough example: If you cut a circle hole in a box and then sketch something that touches the edge of that hole, it's now coincident to it. If you go back, and delete that circle and put in an oval instead, to you it might look like the same hole with a different shape, but to Solidworks you've just removed one reference line completely and added a new one. It can't predict that you wanted this new hole to mean the same thing that was there before, so it just looses the reference. This goes for all of the shapes that make up your part.

             

            It's a bit hard to describe without images. Can you post some screenshots of issues that you are having?

            • Re: "Sketch contains dimensions or relations that no longer exist"
              John Stoltzfus

              Matthew Robertson - Welcome to the forum - How long did you use SW? and How much training did you have also what version of SW are you using??

               

              Your question tells me that you need to look at how you relate the sketches in your model.  Are you working on just one part or an assembly?  Ian Moore gives a great example and there are ways to avoid what you are experiencing..

                • Re: "Sketch contains dimensions or relations that no longer exist"
                  Matthew Robertson

                  Hi John! Thanks for the words of welcome. I am almost completely self taught with SolidWorks, and I've had a few years to work with / learn the platform. I think Ian did indeed touch on exactly what the cause is, I had a gut feeling that was the issue, but I don't consider myself to be an expert hence why I came seeking advice. I think you are correct in your assessment, and better understanding the way SolidWorks "thinks" and behaves can only benefit me. I'm making modifications to just a single part, and then rebuilding an assembly of two parts mated together to see how it fits and interacts. With the assembly the mates sometimes give me an error, but it's completely evident why. I just had issues with the single part file because I had modified sketch relations as you pointed out.

                • Re: "Sketch contains dimensions or relations that no longer exist"
                  Glenn Schroeder

                  Welcome to the forum.  Can you post your Part file here?  That would make it much easier to help you diagnose the issue.  See How can I attach a file to a forum post? if you aren't familiar with the process.