We cut up manila folders and staple or tape them in my office all the time. Less glamorous than the Fischer technik stuff but works really well for all kinds of structural ideas. We have modeled adhesive connections, switchback stairs, wind tunnel cladding, glass cylinders, a folding mechanism for a gate, vierendeel trusses, an idea for an origami canopy and tons of other stuff. And it always saves a ton of time bc you get to the right answer and it lets the FEA just be a check.
The thing about manila folders as opposed to Lego or something is that
1. You always have materials on hand
2. you can make surfaces as well as beams
3. You can make any 2D shape or any developable surface
4. You can make "pins" with a stapler
5. Its really quick
6. its thin enough to capture buckling behaviors
7. If you add in rubber bands you can visualize stress.
8. You can print on it from CAD if you need to make accurate cutouts
I used to use foam core board, but its almost an order of magnitude slower and less flexible. I literally just start cutting with scissors and don't even trace it out with a pencil first. Bc its so cheap and quick you can afford to iterate like a dozen or more times.
We have a hot glue gun on hand too, though doesn't see much use these days. We also have a 3d printer which frankly is not very useful for this kind of thing.
