Circles Aren't Circular?

I’m attempting to round one edge of a shelf in SketchUp. The shelf is 3/4" thick, so I’ve drawn a circle with a 3/8" radius, 3/8" in from the edge, and used the follow me tool to round off the edge. This worked fine on one shelf, but on the next, for some reason, the circle extends past the edges of the shelf vertically, but not horizontally. The tape measure says it’s 3/8" in every direction, the shelf is 3/4" thick, and the center of the circle is at the midpoint of the shelf. So why is it noticeably larger vertically than horizontally? I’ve tried adjusting the number of sides to the circle, but it doesn’t seem to help.

Is there any way to make SketchUp draw circles that are the same size in all directions?

It’s a bit tricky to understand what you are trying to achieve over texts. Would you be able to upload an image or skp file that you are working on?

Need more info. Model or at least screen shot.

But at a guess it sounds like your circle wasn’t perpendicular to the path.

SU can only draw a circular circle, however you can modify them deliberately or through error…

one being what ‘speedier’ @Box just beat me too…


After reading your post several times, I think I understand what you are describing. It sounds to me as if you aren’t always dragging out the radius of the circle on axis. That would have an impact on the apparent shape of the round over.

Best practice is to drag out the radius of circles on axis and be consistent about it.

I wonder, though, why you are using a circle for this job. It’s not the best tool. Instead, I would use one of the Arc tools to draw a semi-circular arc. Locate the ends of the arc at 3/8-in. from the edge of the shelf and drag out the radius.

Edit: Box might have it if the shelf isn’t a straight line and you’re not starting the profile perpendicular to the first segment in the path.

First, thanks for the advice!

The shelves are all simple boxes – rectangles pulled three-dimensional. I was using the circle tool because I hadn’t thought of using the arc tool. :slight_smile: But I was using it correctly, dead center on the axes, on a guide line 3/8" away from the edge of the shelf.

I came back to it this morning, after reading your responses, tried all sorts of things, and finally discovered the problem. I was using a guide line set up for the shelf above the one in question. It should have worked properly. The shelves are perfectly aligned, and the tape measure says the guide is 3/8" from the edge of all of them, but for some reason SketchUp thinks it’s at different distances for each shelf. Strange, but a quirk I can learn to avoid.

I also learned that it can take multiple attempts to get a circle that fully cuts off the parts that need to be excised in order to make the rounded edge, because circles in SketchUp are actually polygons. This may be obvious to everyone else, but it had me scratching my head for a while. :smile:

Thanks again for the help!

Out of curiosity, what is the precision setting in Window>Model Info>Units? I’m guessing the precision isn’t set very high. this would lead to errors and make you think that the shelves are perfectly aligned when they are really off by a tiny amount.

The precision is set to 1/64". I wasn’t aware that this could be a problem, but fortunately the default appears to be the most precise setting.

It would be interesting to see the SKP file.

Sure, here it is. I anticipate a number of moves in the near future, so I’m putting together some furniture I can easily disassemble – thus the interlocking shelves. I had no idea that rounding the ends of the shelves would be problematic, so if it turns out I’ve done something wrong, please do enlighten me. :slight_smile:

Nomad Zen Bookshelf.skp (226.6 KB)

It shouldn’t be that difficult to round over the ends correctly although the Arc tool and Push/Pull would be more than adequate for the job. I did find one shelf misaligned a bit. See the selected one in this screen shot.

And a close up of its end. The guideline is aligned with the extreme end of the other shelves on that end.

Odd. I aligned things by snapping them to other objects. Thanks for catching this!

You’re welcome.

Did you put all the shelves and verticals in place before rounding the ends?

By the way, you might find it easier to see tiny errors if you change Profiles to 1 in your style edge setting. In the following screen shot I have done that and orbited around to the back edge of that shelf. There’s a little gap toward the left side and the shelf overlaps the vertical piece on the right. With the thicker lines it can be difficult to see that stuff.