To keep the screen from becoming cluttered, the hitzones are not always visible. According to the World of Tanks Portal , the markers appear based on your viewing distance:

While this specific version (0.9.13) is outdated for the current live client of World of Tanks, similar "Discrete Hitzones" are still maintained for newer versions (e.g., 1.26.1.1) on community hubs like WoTportal.cz .

Hitzones are visible from up to 300 meters away. Legacy Status and Usage

While informational hitzone skins that only show where modules are (like this one) are generally permitted, always check the Official Fair Play Policy before installing mods. 3D hitzone mods that make tanks transparent to show modules in real-time are strictly prohibited and can lead to permanent account bans.