Pain
Pain is a stat: How much pain a person feels. Its default value is 100%.
Most biological creatures in Rimworld feel pain caused by injuries. Extreme pain causes colonists, raiders, and animals alike to go into shock. Pain causes unhappy thoughts. Once pain passes 10%, it'll start to have an effect on consciousness.
Most pain is temporary, but scars and certain diseases can cause long-term or permanent pain. A Painstopper implant will get rid of all a colonist's pain and negate any pain-related mood penalties. Note that colonists with the Masochist trait get a mood bonus from pain instead of a penalty, so it's usually better to leave them alone.
Formula
Pain follows a somewhat painful formula:
Pain = Number of Injuries ÷ [80.0 × Max Pain Level Multiplier[1] × Health Scale[2] + Extra Pain ÷ (80.0 × Max Pain Level Multiplier)]
Extra pain is determined by individual injuries:
Extra Pain = Injury Damage × Injury Pain Value
- 50 crush damage would do 50 damage × 1.25 crush pain = 62.5 extra pain
- 50 burn damage would do 50 damage × 1.875 burn pain = 93.75 extra pain