Dome Cutting Issues with Archway

[Whiteowl77]

I am having problems with cutting an Arch out of a Dome Shell.
The Arch and Dome have a very high Polygon Count (222 sides). When I use the intersect tool, the resulting geometry is less than an ACCURATE perfect geometrical cut. The Edges remaining after deleting the interesting geometry, tends to leave the edges Flared out a Bit (if u look very very close).

I am trying to cut an Oval Hole (18' Wide x 7'-7.25" High) in the Center of the Dome (23' dia, 12.5' High). Dome centerline is 1.5' above horizontal.
I want a nice clean cut, punched out from the front. When I cut from the front, the side elevation shows an uneven arch entrance. When I cut from the side, the front elevation shows the wall thickness (which is not desirable). I have used EDIT: intersect with Model, and Used intersect selected, - but with similar results.
My Arch opening and dome are both complex polygon shapes with and arch side count of 222.
Any ideas here. I posted a few pics & the SKP file here for feedback.

Thanks Guys,
Whiteowl77

[mitcorb]

I am not seeing your illustrations. Please try to upload again.
While we wait, the inaccuracy you speak of may be partly because of a low segment count on the dome, or the arch? Did you build the dome from scratch or insert from the Sketchup Components library?

[Gaieus]

He posted the file to me. It was impossible to attach here as it is 9Mb+.

To me, the intersection seems to be pretty smooth (regarding SketchUp1s nature to segmenting everything) but if really smooth results are needed, you need to make everything so detailed. The arch was made of really high segmented arcs, the dome way made of a really high segmented arc as the face to be lathed however the circle around which you lathed it is still the default 24 segmented circle.

Such an intersection will always be somewhat segmented but if you are ready to sacrifice workability for smoothness and precision, you need to do it including all elements of the model.

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