3. Killers - people who sees killing as the soul purpose of the game, they typically believe
that a player's status depends on how many creatures or other players his/her avatar has
killed.
4. Explorers - people who roams around the gameworld to discover new places, features,
items and non-personal characters.
In general, social status in the MMOG is usually the underlying motivation for all player
types in MMOGs [10].
Both players and non-personal characters are represented as mobile agents with a
sense-reason-act approach in Zereal, this is because they need to have autonomous, social,
reactive, and pro-active capabilities, hence following the weak properties of agents [25]. The
selection of agents as the primary abstraction is also motivated by previous representations
of intelligent life-like entities in virtual environments [6, 3] Mobility is selected since the
players have to move in a world topology that is spread out on several computational nodes,
mobile agents have previously been used in various virtual environment architectures [16].
2.6
Non-Personal Character Models
For our platform we chose the non-personal characters models to be equal to player models
of the type killer, but with minor alterations regarding mobility. The alterations are that NPCs
are less mobile than the killers, i.e. they mainly stay within the same subworld at all times.
2.7
Zereal Sense-Reason-Act Approach
SENSE
REASON
Scan Gameworld
for Players, NPCs
and Items
ACT
Select action based
on Sensing and
1. Markov-matrix
OR
2. Hierarchical Plan
(Try) Selected Action
- Fight
- Move (A*)
- Chat
- Pick up/Use items
Figure 4: Zereal Agent Architecture
Simulated players and NPCs senses using a scan-based vision algorithm that have a con-
figurable vision radius. The vision algorithm can detect walls, items, (other) players and non-
personal characters.
There are three types of reasoning mechanisms for players and NPCs in Zereal:
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Scalable MMOG Player Simulation