How does the Center-to-Edge (CTE) aiming system work?
CTE (Center-To-Edge) is an “align-and-pivot” pre-shot routine and “aiming system” that uses a line through the center of the CB and outside edge of the OB as a reference. There are several different versions and interpretations of CTE, but they are all based on establishing an initial “alignment” and then “pivoting” to the final aiming-line direction.
CTE Version 1 (an early version of CTE) – 3 pre-pivot alignments:
Here is a description of an early version of CTE taught by Hal Houle, also known as the 3-angle system:
For a “thick hit” (a small cut angle, less than about 15°) to the left:
- Align the cue 1 tip to the right of the CB center through the right edge of the OB.
- Place the bridge hand down with the cue along this line.
- Pivot the cue until the cue is pointed directly through the center of the CB.
- Stroke perfectly straight along this line.
For a “half-ball hit” (close to 30°) to the left:
- Align the cue through the center of the CB and through the right edge of the OB.
- Place the bridge hand down with the cue along this line.
- Stroke perfectly straight along this center-to-edge (CTE) line.
For a “thin hit ” (a large cut angle, more than about 45°) to the left:
- Align the cue 1 tip to the left of the CB center through the right edge of the OB.
- Place the bridge hand down with the cue along this line.
- Pivot the cue until the cue is pointed directly through the center of the CB.
- Stroke perfectly straight along this line.
Here’s a more-recent clarification from eezbank:
The way Hal taught the system you pivot on every shot. So, the halfball info is wrong. Also, where I use the one tip reference Hal says it doesn’t matter how many tips you use. You can start all the way to one side of the CB if that’s what works with your pivot length.
CTE Version 2 (posted by Shawn Armstrong, as taught to him my Hal Houle) – 4 pre-pivot alignments:
The direction of the pivot, and the starting point, are determined by the angle of the cut. This is why you need to know the half ball hit angle. The alignment point on the object ball is always the outer edge. The starting point on the cueball is always the edge. However, it can be the inside or outside edge. That is determined by the cut angle.
For shots less than 30°, line up the center of the cueball with the edge of the object ball. Start with the outside edge of your cue tip lined up with the outside edge of the cueball. Pivot towards center. Your pivot should be leading you towards the center of the object ball.
For cuts greater than 30°, but less than 65, the pivot comes from the inside edge of the cueball. When you pivot to center, you should be going towards the outside edge of the object ball, away from the center.
For thin cuts, the pivots are edge to edge. For cuts between 65-80° (thicker than 80), the pivot is towards center from the outside edge of the cueball. For cuts thinner than 80, the pivot is from the inside edge of the cueball.
Thinner than 80, pivot from outside edge to center on the cueball, with the starting alignment being cutting edge of cueball to the cutting edge of the object ball. For razor cuts, line up outside edge to outside edge, and pivot away from the edge.
CTE Version 3 (posted by Dave Segal on Spidey’s blog) – 2 pre-pivot alignments:
An excellent explanation and illustration of this approach, from mohrt, can be found here.
Note: CTEL = Center-to-Edge Line = line through CB center and perceived OB outer edge.
BASIC CTE PIVOTS (as taught by Hal Houle):
For thick cuts: Your cue is parallel to the CTEL with your tip pointing at the outside edge of the CB (the edge of the CB that’s farthest from the pocket). You then pivot your tip towards the pocket until it reaches CB center.
For thin cuts: Your cue is parallel to the CTEL with your tip pointing at the inside edge of the CB (the side of the CB that’s closest to the pocket). You then pivot your tip away from the pocket until it reaches CB center.
If you’re not sure which side to pivot from, only one will work. One will look right – the other will not.
For straight-ins: It doesn’t matter which side of the CB you address, just make sure you perform a thick-cut pivot.
Here’s a more recent clarification from Spidey (based on a phone conversation):
What qualifies as a “thick cut” or “thin cut” isn’t strictly based on the cut angle needed for a shot. It also depends on the distance between the CB and OB. You develop a sense for this as you work with the system.
CTE Version 4 (as interpreted by dr_dave from the description and examples on Stan Shuffett’s Pro One DVD) – 6 pre-pivot alignments:
While standing, sight through the center of the CB and the outside edge of the OB (i.e., sight along the CTE line). Then, based on the type of cut (see the table below), shift your sighting to visualize a line through the inside edge of the CB to a given alignment point on the OB (see the table and figure below), while also maintaining the CTE visual. Then drop and slide into your stance straight toward the CB, placing your bridge to align the cue 1/2 tip off the CB’s center (per the table and figure below). Now pivot the cue to the center of the CB with a fixed-bridge pivot. Here is a summary of the OB alignment points and pre-pivot tip positions for each type of cut:
| cut type | OB alignment | cue tip alignment |
|---|---|---|
| straight-in | inside 1/4* | outside |
| very thick cut | inside 1/4* | inside |
| medium thick | center | outside |
| medium | center | inside |
| medium thin** | outside 1/8 | outside |
| very thin** | outside 1/8 | inside |
inside: on the side of the ball toward the cut (i.e., the left side for a cut to the left, the right side for a cut to the right)
outside: on the side of the ball away from the cut (i.e., the right side for a cut to the left, the left side for a cut to the right)
*: If the CB-OB distance is less than about 1′, sight to “inside 1/8” instead of “inside 1/4.”
**: For thin cuts, you ignore the CTE visual and just sight for the 1/8-ball overlap.
You also need to adjust your bridge length for different CB-OB distances, based on the following table:
| CB-OB distance | > 2′ | about 2′ | about 1′ | < 1′ | very close |
|---|---|---|---|---|---|
| bridge length | 8-9″ | 7-8″ | 6-7″ | 5-6″ | very short |
Note – Stan uses the “A,” “B,” and “C” notation (see the illustration above) to refer to the inside, center, or outside of the OB. With a cut to the left, the inside is “A” and the outside is “C.” With a cut to the right, the inside is “C” and the outside is “A.” “B” is always the center. For example, with a “very thick” cut to the right, you align the right (inside) edge of the CB with point “C” (inside 1/4). With a “very thick” cut to the left, you align the left (inside) edge of the CB with point “A” (inside 1/4). Also, Stan indicates the pre-pivot cue alignment based on whether the cue tip is “left” or “right” of center. For example, with a cut to the left, if the pre-pivot cue tip alignment is to the right (outside) of the CB center, Stan calls this a “right pivot.” If the pre-pivot tip alignment is instead to the left of center (“inside” for a cut to the left, or “outside” for a cut to the right), Stan calls this a “left pivot.”
You develop a feel for the alignments and pivots required for different shots based on practice and experience (i.e., there is no direct guidance on how to judge and choose the proper cut category for a given shot). You can also vary the cut angle created with a given CB-OB distance and a given alignment choice by varying your eye position some, also based on practice and experience.
Here are some example shot layouts and alignments (from Stan’s first CTE Pro One DVD), originally posted by mohrt on AZB.
Here’s a demonstration of how the pivots work. Stan has numerous videos covering all aspects of the system on his YouTube Channel.
And here’s a basic demonstration of the system by Lil’ Chris.
from Stan Shuffett (from AZB post):
Previously, I added A and C as thin cut OB aimpoints. That was my first adjustment in 2 years to CTE PRO ONE.
After much study and consideration a FINAL adjustment in my CTE PRO ONE system is being implemented.
For shots at or near a zero angle and with CB and OB further apart than 1 diamond’s distance, please note this change to your visuals.
Instead of using OBA or OBC as an aimpoint for the near zero angle shots, use CBE to OBE with a center to edge perception. All pivot information remains the same. Near zero angle shots can have slight left or right cuts.
This is my FINAL adjustment for any major system aspect of CTE PRO ONE.
from AtLarge:
After DVD1, Stan adjusted the visuals to include C (without a coupled CTE visual) for left cuts and A for right cuts, both with left or right pivots. So it would now be 8 instead of 6 in each direction.
[Although, ] A-left and B-right are now considered to produce the same result for left cuts.
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