extruding a non linear shape

[greenwoods1462]

hello in the attached file I have a roof section I want to extrude the inner curve to make it flat.  The ooutside would stay the same but the inner roof body would be flat not curved like a solid D body.....

many thanks in advance for any help

[jhackney1972 · Accepted solution]

Is this what you had in mind?  If so and you need more on how I did it, just let me know.  If it is not what you desire, please clarify in detail what you exactly want.  Model is attached.