Intersecting 2 Half Circles

In drawing a model of a dome, I want to place a smaller half circle over the top of a larger half circle and have the base plane of the smaller half circle ‘cut’ the larger one so that the portion of the larger half circle above where the smaller one intersects it is removed.

I’ve tried Intersect > with Model and > with Selection but I’m not getting the result I want which is to remove the portion of the larger half circle ‘below’ or ‘inside’ the smaller one.

I’ve read tutorials but I get confused by the explanations because they, of course, explain the whole logic and process but don’t make simple statements like ‘cut out the intersected part.’

I’ve tried having each half circle group selected for editing in turn and both selected without success. I’ve tried simply moving the smaller one and copying and pasting it. Still no cigar.

If someone could post the steps simply, starting with select ?, I’d be very grateful.

Share your SketchUp file so we can see what you are trying to do.

Here you go, Dave. Thanks for the help.

A few notes: the larger ‘dome’ has an 23’4" diameter while the smaller one has a 6’ diameter. The smaller one has a solid edge across the diameter while the larger one does not. The larger is supposed to be a green tinted translucent glass while the larger is a gray tinted translucent glass. I did this for visibility purposes to help keep me straight. I colored the plane on the diameter of the smaller one for the same reason. Each is defined as its own group. I worked out that I want the smaller ‘dome’s’ bottom plane to be positioned 24" below the top center of the larger one; therefore I dropped a 24" vertical line from the top center of the larger one.
dome file.skp (308.9 KB)

Is this what you are trying to create as the end product?

Or maybe this?

Thanks, Dave.

I want the second but when made translucent I don’t want a plane atop the larger circle you created. Think of looking from below up into a lofted skylight unobstructed by anything except the translucent upper dome.

There is no plane atop the larger partial dome.

Don’t make it so difficult.

Can you hear the sound of palm slapping forehead?

When I get on a tack, I have a hard time getting off it.

Thanks, Dave!

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Dave beat me but here is a SU file to show you all the required steps.

Small dome on top of larger dome.skp (193.9 KB)

Thank you, Jean!

That will get me what I want.