Hi ioVideoMaker, yes like Brian writes above it would help a lot if you could post .3dm model files for the objects you are describing rather than only screenshots.
re:
> DIDNT WORK - the same attempt on a curved surface fails (make planar doesn't work)
I don't know for sure since I'm not able to examine the object you are talking about but usually to make an indentation on a curved surface you'll need to cut up a portion of the surface and then you can extrude that surface fragment.
