Has anyone had any success in building arches with paper? It seems nearly impossible to make bent joints that are stable, and the FAQ's say that an arch needs to have a curved, symmetrical structure.
Also, for tunnels we've been rolling a ping pong ball or a golf ball through our tunnels to test the minimum dimension, if that helps anyone.
Where does it say in the rules that it must be curved and symmetrical? Considering the typical building materials (straws, popsicle sticks, etc.) that is not a practical application for the event. Especially if a load is involved.
As I am coaching the event my guidance is that the primary difference between Arcs and Bridges is that the primary dimension will most likely be height vs. length.
It defines an arch here on the official FAQ page: https://www.soinc.org/mystery-architecture-0
Looks to me like that is a copy and paste of the empirical definition of an arch: https://en.oxforddictionaries.com/definition/arch
I think it would be very hard to judge subjective measurements like curved and symmetrical and instead will be based on the examples in the rules:
For an arch, the Primary Dimension could be measured:
i. with no load, from the base to the highest point of the arch
ii. with a load, from the base to the highest point of the load
The guidance I am giving my team is that an arch is different than a tower because it has to have two supports and span a distance vs. a square or rectangular tower base. But the variability of this event is what makes it interesting so we also emphasize reading, understanding the rules, and asking questions to clarify.