Getting arched windows right (V10)

[Gene Davis]

I know there are few V10ers left, but am hoping the window spec tools in X2 are unchanged enough so I can see a path.

I want to have a ceiling over a three-unit group of transom windows that parallels the arch of the windows. Ideally, the window tops would be a section of a circle, and that means the tool one would use in CAD to make the p'line solid for the ceiling, or the curving tools one would use for a ceiling plane, could work to get concentricity.

The problem I have is that the window tools I use to get the arched segments are hard for me to understand, when it comes to matching radii for the top segments. I just dab away using trial and error until I get something that looks OK.

In the pic attached, the center top window is made using "broken arch," and the flankers use "double arch" to specify. The arched soffit over the window is not concentric with the window heads below.

Can anyone explain, in a tutorial way, how to get three transom windows built and mulled so they all have a common radius to their heads?

We've no trouble getting our window suppliers to do this. Andersen, Pella, Marvin, Eagle, Norco, and all the others will happily comply. My issue is in using Chief Architect to get these shapes exactly as I want.