NV B.67 - The trisect system for draw shots, from VEPS I

[crrazyy]

:30 trisect system final direction is 3 times.. so its close to 90 degrees on most shots. its good for positioning the cue ball. follow through would probably be 15 degrees.

complicated...i could be wrong

[DrDaveBilliards]

@crrazyy

It's close to 90 degrees only for shots close to a 1/2-ball hit (30-degree cut angle), and for "good" draw action.

Dr. Dave

[Acharn2]

@DrDaveBilliards I thought the 90 degree rule applied when there was no spin on the cue ball, either forward or backward. That's why it's so important to master the stop shot.

[DrDaveBilliards]

@Acharn2

That is correct. The 90 degree rule does apply only for a stun shot, where the CB has no top or bottom spin. The 90 degrees is the angle between the final CB and OB paths. With a 1/2-ball hit good-action draw shot, the CB's angle changes by 90 degrees, but the angle between the final CB and OB paths is much greater than 90 degrees (120 degrees).

I hope that helps.

[BillyJackets]

there never seems to be a lack of knockers whenever someone tries to help people . I consider myself a very good player and I have learned how to fine tune my pool game with lots of the info Dave has supplied ....thank you Dave and please ignore people who don't understand that you are giving a starting point to work from.

[DrDaveBilliards]

Thanks.  I appreciate your supportive message.

[cfrosty6]

@BillyJackets here here

[rob3c]

As you know, it's only accurate for cuts near 1/2-ball hit (30 degrees).

For example, the trisect system predicts 180 degree draw (i.e. straight along the aim line for a 60 degree cut (1/8-ball hit). That's obviously wrong, and is 40 degrees off!

Also, fuller hits up to ~3/4-ball are more like 4x the cut angle instead of 3x.

If you're going to use approximations that are only valid in a certain range, why not tell the viewer?

[DrDaveBilliards]

The DVD has much more detail than this single demo clip. It is made very clear that the trisect system only applies for cut angles up to about 40 degrees, which is about the largest angle most people can form comfortably with a stretched peace sign. So if you can measure the cut angle with your peace sign, the method works very well. continued ...

[iralee3c]

@DrDaveBilliards

This advice might be helpful for playing extremely general zone-position in pool, but seems too rough for ball-to-ball play. More precisely, full-draw carom angles for cuts up to about 40 degrees hovers near 2.3-2.4x of the cut angle (for almost the entire range!). Using 3x the angle as an approximation is too far off base to use as a guide to score on distant targets (balkline) or for drawing the ball onto a fine line (in 3-cushion)- I fear it might lead to stroke confusion.

[DrDaveBilliards]

The trisect system applies only for a "good action" draw shot, which is defined as the amount of the draw that creates 90-degree deflection for a 1/2-ball hit. As you point out, it is possible to draw more than this with "full draw." It is also very easy to draw much less than this. The trisect system is simply a reference that is very easy to visualize. However, you need to be able to adjust relative to the reference (as is demonstrated on the DVD).

Thank you for the comments,

Dr. Dave