We’ve all been there – you’re modelling away happily but when you try to create a Revolved Base/Base feature SolidWorks throws up that dreaded error: “The Sketch is open, self-intersecting or intersects the centreline”:
This a very common problem and one that can be extremely frustrating but luckily it is usually fairly easy to troubleshoot and fix.
Listen to SolidWorks
One of the great things about SolidWorks is it often gives you pretty good information about what’s going wrong. You just have to understand what the program is trying to tell you. It can be very tempting to just click error messages away, but it’s always worth taking the time to read them and find the problem. In this case our error is telling us three separate things, we just have to narrow down which of these problems we’re facing:
“The Sketch is open”
Unless you’re creating a Thin Feature Revolve then SolidWorks can only Revolve a closed profile. This means that you need to have no gaps or breaks around the outside of your profile.
Try using an Extruded Boss/Base to check whether your profile is closed. If you can’t Extrude the profile then it probably isn’t fully closed. You can also use the Select Chain (right click on any line in the Sketch) option to help find gaps.
Any outer lines of the profile must also be solid lines. Construction/Centrelines count as gaps in the profile. Make them solid by selecting them, then unchecking the ‘For construction’ box on the left.
“The Sketch is self-intersecting”
This is a fancier way of saying that parts of your Sketch overlap each other. It can also include single lines that are only connected at one end. Make sure that the outer profile consists of just one chain of entities.
This part of the error can also cover two lines drawn in the same place, one on top of another. These areas can be hard to spot so use the Select Chain option to track them down.
Check out the video for a detailed explanation of how to fix this problem.
“The Sketch intersects the centreline”
This simply means that the profile can’t directly cross over the centreline. You can have profiles on both sides of the centreline, as long as you don’t actually cross over it.
Three Tips for Successful Revolves
When making Revolved features try to ensure that you:
- Use a closed profile, with no gaps or breaks (construction lines count as gaps)
- Avoid lines that self-intersect – eg. lines that cross over each other or are drawn on top of each other
- Make sure that your profile doesn’t cross the centreline.
By checking these three areas you should be able to find and fix your problem. Happy modelling!
About the Author: This is a guest post by Johno Ellison, a design engineer with over fifteen years or experience, who specializes in SolidWorks 3D CAD modeling. Johno is the author of the following online SolidWorks courses:
Master Solidworks 2019 – 3D CAD using real-world examples
Master Solidworks 2018 – 3D CAD using real-world examples
Master Solidworks 2015 – 3D CAD using real-world examples
