Guards don't spot you instantly. Their suspicion builds over a couple of seconds, and how fast it builds depends on how close you are and how well lit you are.
How spotting works
While a guard can see you, their alertness climbs. It takes up to about 2 seconds of sight to alert them and about 4 seconds to detect you. Up close or in bright light, it happens much faster. Break line of sight and it stops building. The icons over their heads show where they're at. See Enemy Alert States.
CarefulWalking into a guard gives you away immediately, and so does a guard finding a body you left in the open.
What makes you harder to see
| Factor | Effect |
|---|---|
| Darkness | The less light on you, the shorter the distance you can be seen from. Night, shadows and shot-out lights all help. |
| Crouching | 1.5× harder to see than standing. |
| Prone | 2.25× harder to see than standing. |
| Underwater | Visibility drops to 20%. |
| Tall grass and bushes | Invisible while crouched or prone. |
| Medium grass | Invisible while prone. |
| Tree Suit | A wearable ghillie suit for blending into foliage. |
When you settle into cover, a camouflage pattern fades onto OniOne. That's your cue that you're hidden.
Lights
Floodlights, wall sconces and tube lights can all be shot out. Guards fight back, though: they may switch on lights near you, or shoot out their own lights if you're sniping from the dark. See Guards.
Sound
Being unseen isn't enough. Guards also hear you. See Noise.