The Bush Is Small on Screen, Not in the Collision System
A game does not usually calculate a tank’s movement from every visible leaf and branch. Instead, it checks the vehicle against simplified shapes called collision geometry: invisible boxes, capsules, or rough mesh surfaces that mark what can block movement. A bush may look delicate, yet its collision shape can extend across its whole clump—or even beyond the leaves players can see.
When the tank’s movement would overlap that shape, the game’s physics system may stop it rather than let it pass through. The check is about whether two collision shapes intersect, not whether the obstacle seems strong enough to halt an armored vehicle. Unless the game has a special rule for crushing vegetation, the bush is simply another solid object.
Why Developers Give Scenery Collision
Making every plant passable can create different problems. Vehicles might drive through cover that is meant to shape a route, or move through scenery in a way that looks visually wrong. Solid objects can also help define boundaries and keep vehicles from clipping through terrain or other props.
The tradeoff is precision. A detailed collision shape for every branch would cost development and computing effort, while a simple shape is easier to build and test. But if that shape is too large, too rigid, or poorly matched to the art, players encounter invisible resistance: the tank appears to hit a harmless sprig when it has actually struck the bush’s hidden boundary.
That mismatch can become part of a game’s memorable friction. The vehicle is not losing a contest of strength; it is obeying a rule the scenery’s appearance does not reveal.
