A mini ruler provides a physical, straight edge to visualize the trajectory. By placing the ruler on the table to connect the object ball to the bank point, and then from the bank point to the pocket, you can visualize the path instantly.
Aim an object ball directly at a side cushion at a sharp angle. Hold the ruler against the screen to check if the exit angle matches the entry angle toward your target pocket. Adjust your spin and power to see how speed changes the bounce path. Drill 3: Cue Ball Position Planning mini ruler 8 ball pool better