There are a variety of plugins/extensions that can flatten geometry. TIG's Flatten to Plane is a good one. You can get it from the Sketchucation Extension Store.

Thank you TIG! One click - problem gone! Cheers, Jeff O.

Dave R. - Thank you so much! I'll give that a try. Cheers, Jeff O.

Should be the same with Flowify but seems this case has some few faces missing in the result! :
A little more more tricky than Shape Bender but more versatile) 😉

same_flowify.skp

should_be.jpg

@dave r said:

...What Pilou is trying to say is ...

😄 😄 👍 so funny !

It's better if you post an image and more an skp file (save as V6)! 🤓

Else I don't see why you have this problem! 😄

https://s6.postimg.org/jsc4dqpe9/GIF_circle.gif

Guides are drawn following a previous one as inference line!

https://s6.postimg.org/euyjsmnf5/GIF_circle1.gif

Circle is drawn with taking the orientation of the face by Shift!

https://s6.postimg.org/7t57k6975/GIF_circle3.gif

First guide is drawn by a move and come back! 😉
(move & back can be external or internal as following)

https://s6.postimg.org/bqsh9kw0h/GIF_circle4.gif

Cotty,

Thank you!! You are a gentleman and a scholar! I was able to reproduce your excellent results. This has, with your help, suddenly become a great day. Cheers, Jeff

OK - I now know the the process. Here it is:

From web-based topographic server (MnTopo in my case), zoom in to subject area, download "Contours" (not DEM). Zipped file e-mailed to you containing shapeless. Open in ArcGIS and back save to AutoCAD 2010 or earlier. Open file in Auto CAD, create bounding box, and clean up stray contours. Save as a .dwg . Open .dwg in SU and save as .skp et voila!

Cheers, Jeff