ValueError: Can't normalize Vector of length Zero

[simsimiSION]

File "/gobigger/balls/clone_ball.py", line 152, in move self.direction = (self.vel + self.vel_last).normalize()

[mingzhang96]

Thanks for your issue! I check the related code:

if self.vel.length() > 0 or self.vel_last.length() > 0:
    self.direction = (self.vel + self.vel_last).normalize()

This error may be caused by the situation that (self.vel + self.vel_last).length == 0. We can prevent this by adding more judgments.