Another strange behavior:

Since Obj2 can collide with Obstacle, so I duplicate Obstacle into 4 new entities and scale to become wall. Place them along the stage end (my Invisible Stage Bounding still remain).

So I run the game, and yeah!!! Obj2 can bounce when reach the end of the Stage (thx to the new dummy walls derived from Obstacle). But then, I pan the Obj2 to 70 degree. Guess what? Obj2 can penetrate again!!

If I can't find the solution, I have to hard code the bounding myself like this:
Code:
if (Obj2.x > 800 ) Obj2.pan = 180;
if (Obj2.x < -800 ) Obj2.pan = 180;
if (Obj2.y > 800 ) Obj2.pan = 180;
if (Obj2.y < -800 ) Obj2.pan = 180;

But this method, how to handle if the angle of Obj2 isn't 90 degree? Like 70 degree... crazy