Here is my challenge. Its based on a barn near my neighbor hood. Three objects, each with done slightly differently:
The Silo is a cylinder was extruded once and top vertices were merged at center.
The Barn was extruded up twice. Each time the top vertices were scaled on the X axis. And finally the top 4 vertices were merged at center in two different operations; once for the front, once for the back.
The Roof was trickiest of all. I tried 4 or 5 techniques before I found something that I just ended up brute forcing my way through. So the way I did it was to turn on “snap”, snap with “closest” and “align rotation to target”. Then I added 4 cubes to the scene and moved them to each of the separate sections at the top of the barn. This gave me the z axis rotation for each roof plain.
Then I painstakingly grabbed each face of each cube and moved it around to cover the roof to the exact edge. Then I extruded the top and bottoms of each panel to cover the gaps. Then I focused on each individual overlap section (6 total, 3 front, 3 back) and merged the vertices until I ended up with something that looked correct. Finally I raised the bottom set of vertices to give it a lower bump-out.