As has been discussed from time to time (a euphemism for ad nauseam), fractional aiming systems would appear to require an adjustment method for shots that don't fall exactly into the categories of half-ball hit (center-to-edge) or the other general aim guides.
I'm told that Hal Houle recognises this and recommends the adjustment method diagrammed and described below.
In this example the pot required is a thinner hit than half ball, lets say 35 degrees.
The black lines represent the Center-to-Edge aim and the resultant undercutting that would result.
The red lines represent the resultant aim after a rightward bridge adjustment and the resultant OB track.
The brown line represents a parallel line to the black line after the bridge adjustment. The player needn't aim along this line, but if he does, he needs to pivot back to the center of the CB before taking the final stroke. The important aspect here is that the bridge needs to shift right in order to cut the object ball further to the right.
Conversely, if undercutting was required, the bridge would need to be adjusted to the left.
Some Pros and Cons of this system / adjustment method.
This system will allow infinite contact points, hence infinite angle possibilities. Therefore it can theoretically aim for any shot.
The amount of adjustment left or right relies on a lot of intuitive adjustment and hence a lot of practice to develop the eye for when and by how much pot angles are thicker or thinner than the basic categories.
Then, the amount of bridge adjustment needs to be determined and this will be affected by the following variables:
1. Distance of CB to OB: (Adjustment Related). The further the CB from the OB, the greater will be the effect of the adjustment compared to the sideways shift in bridge position. eg. If the CB is 6 feet from the OB, it would require about 1/6th the amount of sideways adjustment as for a separation if 1 foot.
2. Distance of CB to OB: (Aim Related). As the CB and OB come closer together, the resultant angle of a Center-to-Edge aim becomes increasingly smaller / fuller than a true half ball hit. For 1 foot of separation it is a few degrees fuller, for smaller distances it thickens the angle so much it is basically unusable.
3. Bridge Length: For a shorter bridge length the amount of sideways adjustment is magnified, hence a smaller adjustment is required. A larger bridge length means a larger sideways adjustment will be required. This may help in fine tuning the adjustments. The cue's pivot point won't have any bearing on this unless you intend to use english.
4. Throw: This aiming system does not take into account the very significant effects of throw according to the amounts of speed and spin. i.e. You might have the shot aimed well for a soft roll shot, but if you hit a power follow shot, the pot will be overcut by about 3 degrees. Conversely, you might aim correctly for a firm follow shot, but if you play a soft stun shot you'll undercut by several degrees.
I think the message is that aiming is a complex art with many variables and no aiming system can provide a pure fix-it-all. At least not one that can't adapt to all the variables.
Colin
I'm told that Hal Houle recognises this and recommends the adjustment method diagrammed and described below.

In this example the pot required is a thinner hit than half ball, lets say 35 degrees.
The black lines represent the Center-to-Edge aim and the resultant undercutting that would result.
The red lines represent the resultant aim after a rightward bridge adjustment and the resultant OB track.
The brown line represents a parallel line to the black line after the bridge adjustment. The player needn't aim along this line, but if he does, he needs to pivot back to the center of the CB before taking the final stroke. The important aspect here is that the bridge needs to shift right in order to cut the object ball further to the right.
Conversely, if undercutting was required, the bridge would need to be adjusted to the left.
Some Pros and Cons of this system / adjustment method.
This system will allow infinite contact points, hence infinite angle possibilities. Therefore it can theoretically aim for any shot.
The amount of adjustment left or right relies on a lot of intuitive adjustment and hence a lot of practice to develop the eye for when and by how much pot angles are thicker or thinner than the basic categories.
Then, the amount of bridge adjustment needs to be determined and this will be affected by the following variables:
1. Distance of CB to OB: (Adjustment Related). The further the CB from the OB, the greater will be the effect of the adjustment compared to the sideways shift in bridge position. eg. If the CB is 6 feet from the OB, it would require about 1/6th the amount of sideways adjustment as for a separation if 1 foot.
2. Distance of CB to OB: (Aim Related). As the CB and OB come closer together, the resultant angle of a Center-to-Edge aim becomes increasingly smaller / fuller than a true half ball hit. For 1 foot of separation it is a few degrees fuller, for smaller distances it thickens the angle so much it is basically unusable.
3. Bridge Length: For a shorter bridge length the amount of sideways adjustment is magnified, hence a smaller adjustment is required. A larger bridge length means a larger sideways adjustment will be required. This may help in fine tuning the adjustments. The cue's pivot point won't have any bearing on this unless you intend to use english.
4. Throw: This aiming system does not take into account the very significant effects of throw according to the amounts of speed and spin. i.e. You might have the shot aimed well for a soft roll shot, but if you hit a power follow shot, the pot will be overcut by about 3 degrees. Conversely, you might aim correctly for a firm follow shot, but if you play a soft stun shot you'll undercut by several degrees.
I think the message is that aiming is a complex art with many variables and no aiming system can provide a pure fix-it-all. At least not one that can't adapt to all the variables.
Colin
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