This paper discusses the structure of decision model in intelligent virtual environment. Intelligent virtual environment is dynamic environment

that is to say it keepes on changing

decision in intelligent virtual environment also should be dynamic

it must be rapid enough to react to the change of environment. To meet the real time and dynamic requirement of decision in intelligent virtual environment

this paper improve the traditional planning method. The time critical A * algorithm is used to implement real time planning

current action is generated only in a predetermined decision time slice

which is different to traditional planing method. action stack is also employed to store the selected action

which is convenient to evaluate the action in time according to the situation of environment

so

we can discard those unreachable targets in time. Based on that

this paper developes a decision agent to instruct the virtual human in intelligent virtual environment. In addition

a small intelligent virtual environment is developed to test the decision model. At last

Influence of length of decision time slice is test

it shows that the suitable length of decision time slice is about 0 3 seconds.