How do I create one continuous wall where the wall thickness varies as in the attached screenshot? I've managed something using the trapezoid or polygon option to create separate sections, but I can't then get them to join properly. If I try to join 2 sections at a corner for example I'm told that this can't be done.
The trapezoid, polygonal wall does not clean up. And if you were to draw such a wall around a room as soon as you join the last corner or connect nodes at the ends of the wall it will turn into a solid wall the size of the room. Also, if you were to place a window or door in such a wall it would extend all the way across the room.
However, there is a way to model a building with walls like what you are showing.
The walls end up being a morph or mesh with holes for windows and doors. Some of the holes you need for doors and windows might be created using SEO. To add a door or window to a wall like that you can you draw a regular wall to hold the door or window, then reduce the wall height to .001" so it won't be seen, then move that wall with its door or window into the hole you made for it in the morph or mesh.
This is +/- the same idea for modeling just about any kind of free-form wall that needs to have doors and/or windows. The polygonal/trapezoidal wall tool can still be a very useful tool in the process of modeling these walls, but probably exploded into a morph for editing into the final shape that is needed.
Keep in mind that if you convert a wall with a door or window in it into a morph the door or window will also be converted into a morph. You may want to place your doors,windows, holes in the trapezoidal,polygonal walls before you explode them into morphs for further editing of their geometry and then replace the resulting morph doors and windows with real doors and windows with the walls that can't be seen.
Not what I had in mind, but clever. I guess I'll stick to doing each wall section separately. I tried the Niche tool, but you can't then put windows or doors in the reduced section because it still uses the original wall thickness.
something else that might be useful to you is to use a Wall Types Legend and Wall Tags since you can't use Composites for the trapezoid/polygon walls. That is if your polygon walls are more than just one monolithic material.