The attached pic shows the smokebox and chimney of a small railway engine. I’ve drawn this full size, the smokebox diameter is about 44", the chimney is about 15" diameter across the rim (top).
Most loco chimneys have a flared base from which a segment is removed, to fit the profile of the cylindrical smokebox.
Inspection of the 3D model structure of the chimney shows that it is made of many small rectangles -presumably I need to remove that part of the chimney which is inside the smokebox, but I can’t simply delete a lot of the rectangles as this would create holes in the chimney above the smokebox surface. How should I tackle this (using SketchUp Make) ?
Note - the chimney is mainly hollow but I have left the bottom few inches as solid.
A supplementary question… Having drawn this full size, I want to scale it down to about 1:50th, but that makes the rim diameter only about 3/16" and the thickness looks much too small to print, so is making it hollow out of the question?!