   Simple Bounding-Sphere Collision Detection
  Comments for the article Simple Bounding-Sphere Collision Detection
  hie i need some help on how to detect collision between cylinder and box ??   ;  Very nice tutorial, but is there any other tutorials to explain collision response for inelastic collisions ?!Thanks;  Nice article, but seems to be a typo. The first condition of Check(3) should be "vv - pv" as it is in the math.   ;  Don't know if you are still looking at this, but there is a small typo where when calculating the formula for d^2 - r^2 = 0 you say you can solve this using the "determinant" instead of "discriminant" as you say later in the article.  Very useful article, though!   ;  The code is correct in Check(3) (pv + vv <= 0). It's the math that is wrong. I was having trouble using this code, so I ended up going through all of the math. It turns out I just  needed to compute t. I was incorrectly thinking that tmin in the code was the t value.If you're interested in the actual t parameter where the collision occurs, do something like this:// (3) Check if the spheres can intersect within 1 frameif ((pv + vv) <= 0 && (vv + 2 * pv + pp) >= 0) {  return false;}// tmp is a term for getting next check into good float range  float tmp = -pv/vv;// tmp2 = -D/(4*vv)//(4) Check discriminantfloat tmp2 = pp + pv * tmp;if (tmp2 > 0) {  return false;}// calculate the t valuet = tmp - sqrtf(-tmp2/vv);return true;   ;  I noticed that the 3rd code snippet didn't work for me when the 3 cases passed.  I believe the reason is because you actually divided by -vv instead of vv as stated in the article.  If I am correct that would make the last line "return ( pp + pv * tmin < 0 );" instead of "return ( pp + pv * tmin > 0 );" because the inequality needs to be flipped when dividing by a negative number which -vv would be.Thank you for the article!   ;  I don't understand how you derived the condition vv + pv <= 0Be grateful if someone could explain.vv + 2pv + pp >= 0 is easy to understand as its just a straight rearrangement but vv + pv seems to spring from nowhere??   ;  In this code the * operator has been overloaded to mean a dot product right.I have not overloaded star in my vector classes so I need to know if its a dot product or a component wise product.And its always nice to tell people if the operator is overloaded or not when dealing with vectors.   ;  Am I wrong in saying that the 2nd check should be:if ( pv <= 0 ) return false;instead ofif ( pv >= 0 ) return false;from the math above I understand that it should be negative when the spheres are moving away from eachother.Otherwise, great article, been looking for an understandable one for a long time!