When, geometrically, do you know you have BI?

referee99 · #1 (**permalink**) Wed Feb 04, 2009, 01:28am

Quote:

Originally Posted by JRutledge

The backboard has nothing to do with that. There is not point on the back board that has anything to do with this kind of call. And the ball must be on the cylinder to have BI if you are not touching the ball. And if you are touching the ball, the ball must be above the cylinder.

Rut, if the ball was pinned by the defender on the gaudy red X in the image in the OP, can we agree that the defender may be touching the ball while the ball was in the imaginary cylinder with the basket as its base?

JRutledge · #2 (**permalink**) Wed Feb 04, 2009, 01:34am

Quote:

Originally Posted by referee99

Rut, if the ball was pinned by the defender on the gaudy red X in the image in the OP, can we agree that the defender may be touching the ball while the ball was in the imaginary cylinder with the basket as its base?

If the touching was not in the cylinder, where the ball touches the backboard might not be relevant.

As I said, I think you are taking a judgment call and trying to make a one size fits all application. If the ball is not in the cylinder, it is not BI. If you think it is in the cylinder (and certain things are present), then call a violation. You will find that at full speed you are not going to get a simple judgment based on a marking. If the ball hits the backboard does not mean it was touched at the very same spot.

Peace

just another ref · #3 (**permalink**) Wed Feb 04, 2009, 01:43am

I think that while it is possible theoretically to use the backboard markings to determine a violation, in reality one would need at least a slow motion replay for this to be useful. See it. Call it. Live with it. This is a call that is very often difficult to make with complete certainty.

referee99 · #4 (**permalink**) Wed Feb 04, 2009, 01:49am

Quote:

Originally Posted by JRutledge

If the touching was not in the cylinder, where the ball touches the backboard might not be relevant.

As I said, I think you are taking a judgment call and trying to make a one size fits all application. If the ball is not in the cylinder, it is not BI. If you think it is in the cylinder (and certain things are present), then call a violation. You will find that at full speed you are not going to get a simple judgment based on a marking. If the ball hits the backboard does not mean it was touched at the very same spot.

Peace

I'm just intrigued by the geometry of it. Just to confirm, I'm talking about a pinned ball. Contacting the ball while it is in contact with the backboard.

I used to have a backboard and rim sitting in my garage. If i still had it I'd go roll a ball around on it and get some empirical knowledge. I am NOT willing to get a ladder out though.

Raymond · #5 (**permalink**) Wed Feb 04, 2009, 08:24am

Quote:

Originally Posted by referee99

Rut, if the ball was pinned by the defender on the gaudy red X in the image in the OP, can we agree that the defender may be touching the ball while the ball was in the imaginary cylinder with the basket as its base?

That would be goaltending, not BI. As JRut has said, the backboard has nothing to do with BI.

BillyMac · #6 (**permalink**) Wed Feb 04, 2009, 06:41pm

Quote:

Originally Posted by BadNewsRef

As JRut has said, the backboard has nothing to do with BI.

This statement is 100% correct, but I believe that referee99 is trying to point out to us that the backboard limits the position of the ball, inside and outside, of the imaginary cylinder, when the ball is behind the basket. If the ball is on either side of the basket, to the left, or to the right, then it is possible for the ball to either be either inside the cylinder, or outside the cylinder. If the ball is in front of the basket, the it is possible for the ball, again, to either be inside the cylinder, or outside the cylinder. What, I think, referee99 is saying is that the backboard may be a limiting factor behind the basket, that is, if the ball is in contact with the backboard, and it's not too far to the left, or too far the right, of the basket, then that ball must, according to referee99, be inside the cylinder. The ball can't go farther back than the backboard, it's against the laws of physics. I'll let someone else work out the math, using the diameter of the ball, and the depth of the flange attached to the backboard. It's 19 degrees outside right now, and I refuse to go out onto my icy driveway, get up on a ladder, and check out referee99's theory on my basket and backboard.

referee99 · #7 (**permalink**) Mon Feb 16, 2009, 06:42pm

Quote:

Originally Posted by BillyMac

This statement is 100% correct, but I believe that referee99 is trying to point out to us that the backboard limits the position of the ball, inside and outside, of the imaginary cylinder, when the ball is behind the basket. If the ball is on either side of the basket, to the left, or to the right, then it is possible for the ball to either be either inside the cylinder, or outside the cylinder. If the ball is in front of the basket, the it is possible for the ball, again, to either be inside the cylinder, or outside the cylinder. What, I think, referee99 is saying is that the backboard may be a limiting factor behind the basket, that is, if the ball is in contact with the backboard, and it's not too far to the left, or too far the right, of the basket, then that ball must, according to referee99, be inside the cylinder. The ball can't go farther back than the backboard, it's against the laws of physics. I'll let someone else work out the math, using the diameter of the ball, and the depth of the flange attached to the backboard. It's 19 degrees outside right now, and I refuse to go out onto my icy driveway, get up on a ladder, and check out referee99's theory on my basket and backboard.

On the side of the court were baskets at 8' height, so I got a chance to play with this.
When a mens basketball is placed so that the vertical center of the ball is aligned with the middle of the outer edge of the 'shooters rectangle' and the ball is touching the backboard, the ball is not touching the cylinder with the ring of the basket as its imaginary base. It is juuust outside of the cylinder.

Move it in 1" and it is touching that imaginary cylinder.

BillyMac · #8 (**permalink**) Mon Feb 16, 2009, 09:21pm

Quote:

Originally Posted by referee99

On the side of the court were baskets at 8' height, so I got a chance to play with this. When a mens basketball is placed so that the vertical center of the ball is aligned with the middle of the outer edge of the 'shooters rectangle' and the ball is touching the backboard, the ball is not touching the cylinder with the ring of the basket as its imaginary base. It is just outside of the cylinder. Move it in 1" and it is touching that imaginary cylinder.

It's tough to argue with empirical data.

JRutledge · #9 (**permalink**) Mon Feb 16, 2009, 09:48pm

Quote:

Originally Posted by referee99

On the side of the court were baskets at 8' height, so I got a chance to play with this.
When a mens basketball is placed so that the vertical center of the ball is aligned with the middle of the outer edge of the 'shooters rectangle' and the ball is touching the backboard, the ball is not touching the cylinder with the ring of the basket as its imaginary base. It is juuust outside of the cylinder.

Move it in 1" and it is touching that imaginary cylinder.

I still say you are making something that is simple into a much more complicated mess. If it works for you, I guess keep up the good work.

Peace