Curved sides losing face

Here is what should be a simple task, but is giving me trouble. I created a square and used push/pull to give it some dimension. Then I created 3 arcs, one on each of 3 faces. When I deleted the outside lines from the arcs, not face was created, nor can I find a way to get the face created. Any ideas? Thanks!

SketchUp only makes faces when the edges are coplanar. Your three curved edges aren’t coplanar so you need some additional edges.

You need to stitch the edges together with the Line tool. Fredo’s Curviloft is another good way to do that.


You have to remember that SU can only produce flat surfaces and there is no flat surface that would join that series of arcs.

When you draw a circle in SU, you are actually drawing a number of straight lines (could be a lot of them or just a few). If you extrude the circle up to form a cylinder, it is not a true cylinder but a series of conjoined flat faces.

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Thanks DaveR - I downloaded the extension and am working with it now. I’ve got it to skin the area once, but I keep getting a notice saying “Contours cannot be interpreted correctly” - I am going back to the corners for my intersections, could that be an issue?

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It might be but if the endpoints of the arcs are connected properly it shouldn’t be a problem. You could try pulling out the faces opposite the arcs temporarily to see if that makes a difference.

How will you be using this rounded corner in your larger model? I have to assume you aren’t just modeling a block with one corner rounded over.

Is your model very small? What is the radius of those arcs?

I think it is also possible to use SketchUp’s native Sandbox tool in order to generate some surface to close such gap. This way would require some manual cleaning and result surface slightly less smooth in contrast to Curviloft, but result can be sufficient enough in certain cases.

It’s a fairly small model - 1 3/8" square.

“Hand stitching” is perhaps faster than cleaning up the Sandbox from Contours result. Idea on the left, smoothed version to the right.


This may be just that you are using the wrong method for this specific shape.
See in the gif
First button produces that error last button makes the surface.

1 3/8" is pretty small, you should have a look here.

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