Why doesn't anything take damage in the Sandbox? Can I test a raid on my base?

In the Sandbox nothing can be damaged or destroyed by weapons — not your buildings, not you, not turrets. Bullets, arrows and explosives all leave everything intact.

That's how the mode is built: it runs locally on your device without a server, and damage is calculated on the server. It isn't a setting that can be switched on.

You can still test your structure. There's no demolition time limit here — in the main game a piece can only be demolished within the first 10 minutes after you build it, while in the Sandbox you can demolish anything at any time, including a base loaded from a save.

So demolish the piece you want to "lose" and watch what comes down with it. Structural collapse works exactly like in the main game, so you'll see whether the base holds without that wall or whether half the build goes with it.

What you can't test here is the raid itself — how much explosive a specific wall takes, how long it holds, and what else the blast catches in its radius. That depends on damage values and has to be checked on a normal server.