Sunlight exposure

Sunlight exposure is a hidden motive possessed by vampires in The Sims 3: Late Night. It decreases every time a vampire is exposed to sunlight. (Players familiar with PlantSim motives from The Sims 2: Seasons will recognize this as the inverse of PlantSims' Sunlight need.)

This motive can be noticed when a vampire goes into shade for a few minutes after getting the Heating Up moodlet, then goes back into sunlight are regains the moodlet shortly afterward. This example shows that the need to keep a vampire Sim in the shade must last longer than the moodlet.

In The Sims 2, if vampire stays outside for too long your sim will die. Vampire sims can also die of Hunger, but the "Hunger" is replaced by "Thirst".