I got what you said but just a little problem: which way to turn? I mean suppse there is an agent moving straight ahead in the forward direction to reach a target and between them lies an obstacle. now at a certain distance the agent detects the obstacle and decieds to turn away. which way should it turn? right or left?

if you draw a straight line between the avoider's center, and the obstacle's centers, then take the line from the avoider to it's destination, whichever side the line is on relative to the center line, is the side you should turn toward.

if you draw a straight line between the avoider's center, and the obstacle's centers, then take the line from the avoider to it's destination, whichever side the line is on relative to the center line, is the side you should turn toward.

Well that's interesting. I'm going to try it and see what the result will be. thanks.

Shoot random rays in a cone ahead of you. 1 per frame. If it hits, immediately shoot another one straight forward. The orientation of the two points where the two rays hit (if the 2nd one hits at all) gives you a picture of whether the obstacle is angled toward or away from your immediate direction of travel. It also gives you an approximate angle that the object is oriented at. Therefore, you could choose to turn far enough to align parallel to the object (or farther).

Shoot random rays in a cone ahead of you. 1 per frame. If it hits, immediately shoot another one straight forward. The orientation of the two points where the two rays hit (if the 2nd one hits at all) gives you a picture of whether the obstacle is angled toward or away from your immediate direction of travel. It also gives you an approximate angle that the object is oriented at. Therefore, you could choose to turn far enough to align parallel to the object (or farther).

Well I understand all you said except the first sentence. "Shoot random rays in a cone ahead of you". what's "in a cone" supposed to be?

You only need worry about stuff you might run into -- which is in front of you, right? If you send out a ray from center front of your agent with endpoints a certain distance in front of you (based on your current speed is good) with locations that are just a bit wider than you are, you are going to pick up stuff that you are potentially going to run into... not just directly in front, but with your "shoulders" as well.