Perception in Practice

One of our players asked for a review of our perception rules, so this post will replace the earlier post about the perception, but there is no change in rules here, though the movement speed option is newer.

Calculating your current perception


All our perception for Chaos Earth is passive, each player will calculate their current perception and then I will roll for the group when there is something to notice. To calculate your current perception:
  1. Decide what your character is watching for. This means deciding on a skill to use, you may pick any skill even one you don't have or one that doesn't exist. Divide your skill percentage by 30% Perception is now 0-3
  2. Add +1 for a minor affinity and +2 for a major affinity to this skill. Perception is now 0-5
  3. Decide how alert your character is AKA paranoia, this can be 0 +1 or +2. Perception is now 0-7
  4. If you have a perception bonus add it, I don't think any current characters do. Perception is now 0-7
  5. If your character is moving at 1/2 or 1/3 speed multiply perception by 2 or 3. Perception is now 0-21

Checking Perception

Let's look at an example of some perception rolls using just three players in a NEMA trailer.

An easy check of 5 would represent something that most people would notice most of the time but *might* be overlooked. For example a disturbance in a crowd. We'll consider that as our example.

  1. As game master I decide there is a disturbance either as a plot element or randomly. Let's say someone is walking through running into people hard enough to injure them.
  2. I decide on a difficulty of 5 for the perception roll. Probably this will be noticed. Rifts® Ultimate Edition™ Page 367 has a list of example perception difficulties.
  3. I roll a d20 for the party behind the screen, you don't know that I did this, let's say I got a 2.
  4. I check the displayed perceptions:
    • The highest number is a 5(total 7), so I ask that player what skill they are using, they're using mechanical engineering and 4 points of their bonus are from skill and affinity. This means they're focused on the vehicle itself so they are not going to notice this, probably I'd treat them as a 1 or a 0--they're looking at the wrong thing.
    • Next there is someone with a 4(total 6), so I ask that player what skill they are using, they're using read sensory equipment with and 2 points from skill and two points from alertness they are close, if they needed a 4 they would have made the check.
    • The last player has a 3(total 5), they're using streetwise, so everything applies. I tell them they see the disturbance. Since they were using streetwise I would say "because you are watching with streetwise you notice an over-important person charging through the crowd, perhaps some sort of local criminal or bully boy, he seems to be shoving people aside faster than they can move out of the way" To actually find out about this person they should make a streetwise skill roll.

As in this example, perception will often determine which character will see something and how they perceive it as much as whether something is observed at all.