Abstract: A golf ball has, on a surface thereof, a rugged pattern composed of a land and a large number of dimples. A method for designing the rugged pattern includes the steps of: (1) assuming a large number of circles on a surface of a phantom sphere; (2) assuming a large number of generating points 16 based on positions of the large number of circles; (3) assuming a large number of Voronoi regions 18 on the surface of the phantom sphere by a Voronoi tessellation based on the large number of generating points 16; and (4) assigning a dimple and a land to the surface of the phantom sphere based on contours of the large number of Voronoi regions 18.

Abstract: A golf ball 2 has a large number of dimples 10 on a surface thereof. The contours of the dimples 10 are non-circular. A standard deviation of areas of the dimples 10 is equal to or less than 1.7 mm2. A ratio of a total area of the dimples 10 relative to a surface area of a phantom sphere of the golf ball 2 is equal to or greater than 80%. By comparting lines CS obtained by projecting sides of a regular dodecahedron, which is inscribed in the phantom sphere, onto the phantom sphere, a surface of the phantom sphere can be divided into 12 units Ut each of which meets the following mathematical formula (I): ?2?(Nt/12)?Nu?2??(I), where Nt represents the total number of the dimples 10 and Nu represents the number of the dimples 10 on one unit.

Abstract: A golf ball has a large number of dimples on a surface thereof. The golf ball meets the following mathematical formula (I): Su?9.0*So?6.04??(I), Where: So represents a ratio of a sum of spherical surface areas of all the dimples to a surface area of a phantom sphere of the golf ball; and Su represents a standard deviation (mm2) of the spherical surface areas of all the dimples. Preferably, the ratio So is equal to or greater than 0.780. Preferably, the standard deviation Su is equal to or less than 2.150 mm2. Preferably, a number of the dimples is equal to or greater than 300 but equal to or less than 390. Preferably, an average Sa of the spherical surface areas s of all the dimples is equal to or greater than 14.00 mm2.

Abstract: A golf ball 2 has a large number of dimples 8 on a surface thereof. A trajectory of the golf ball 2 is divided into first to fourth segments. An average CD1 of drag coefficients CD and an average CL1 of lift coefficients CL in the first segment are equal to or less than 0.225 and 0.180, respectively. An average CD2 of drag coefficients CD and an average CL2 of lift coefficients CL in the second segment are equal to or less than 0.250 and 0.220, respectively. An average CD3 of drag coefficients CD and an average CL3 of lift coefficients CL in the third segment are equal to or greater than 0.260 and 0.220, respectively. An average CD4 of drag coefficients CD and an average CL4 of lift coefficients CL in the fourth segment are equal to or greater than 0.250 and 0.200, respectively.

Abstract: A golf ball has a large number of dimples on a surface thereof. The golf ball meets the following mathematical formula (I): 1.320?L1?1.420 (I), where L1 represents a ratio of a lift coefficient CL1 which is measured under conditions of a Reynolds number of 1.290×105 and a spin rate of 2820 rpm, relative to a lift coefficient CL2 which is measured under conditions of a Reynolds number of 1.290×105 and a spin rate of 1740 rpm.

Abstract: A golf ball 2 has, on a surface thereof, a rugged pattern consisting of a land 10 and a large number of dimples 8. A method for designing the rugged pattern includes the steps of: (1) randomly arranging a large number of generating points on the surface of a phantom sphere; (2) assuming a large number of Voronoi regions on the surface of the phantom sphere based on the generating points; and (3) assigning a land to the vicinity of the contour of each Voronoi region and assigning a dimple to a portion of the surface of the phantom sphere other than the land.

Abstract: A golf ball has, on a surface thereof, a rugged pattern composed of a land and a large number of dimples. A method for designing the rugged pattern includes the steps of: (1) assuming a large number of circles on a surface of a phantom sphere; (2) assuming a large number of generating points 16 based on positions of the large number of circles; (3) assuming a large number of Voronoi regions 18 on the surface of the phantom sphere by a Voronoi tessellation based on the large number of generating points 16; and (4) assigning a dimple and a land to the surface of the phantom sphere based on contours of the large number of Voronoi regions 18.

Abstract: A golf ball 2 has, on a surface thereof, a rugged pattern composed of a land 10 and a large number of dimples 8. A process for designing the rugged pattern includes the steps of: (1) arranging a large number of generating points on a surface of a phantom sphere; (2) assuming a large number of Voronoi regions on the surface of the phantom sphere by a Voronoi tessellation based on the large number of generating points; (3) calculating centers of gravity of the Voronoi regions and setting the centers of gravity as new generating points; (4) assuming a large number of new Voronoi regions on the surface of the phantom sphere by a Voronoi tessellation based on a large number of the new generating points; and (5) assigning dimples and a land to the surface of the phantom sphere based on contours of the new Voronoi regions.

Abstract: A golf ball has, on a surface thereof, a rugged pattern composed of a land and a large number of dimples. A method for designing the rugged pattern includes the steps of: (1) assuming a large number of circles on a surface of a phantom sphere; (2) assuming a large number of generating points 16 based on positions of the large number of circles; (3) assuming a large number of Voronoi regions 18 on the surface of the phantom sphere by a Voronoi tessellation based on the large number of generating points 16; and (4) assigning a dimple and a land to the surface of the phantom sphere based on contours of the large number of Voronoi regions 18.

Abstract: A golf ball 2 has a large number of dimples 8 on a surface thereof. A trajectory of the golf ball 2 is divided into first to fourth segments. An average CD1 of drag coefficients CD and an average CL1 of lift coefficients CL in the first segment are equal to or less than 0.225 and 0.180, respectively. An average CD2 of drag coefficients CD and an average CL2 of lift coefficients CL in the second segment are equal to or less than 0.250 and 0.220, respectively. An average CD3 of drag coefficients CD and an average CL3 of lift coefficients CL in the third segment are equal to or greater than 0.260 and 0.220, respectively. An average CD4 of drag coefficients CD and an average CL4 of lift coefficients CL in the fourth segment are equal to or greater than 0.250 and 0.200, respectively.

Abstract: A golf ball 2 has a large number of dimples 8 on a surface thereof. A trajectory of the golf ball 2 is divided into first to fourth segments. An average CD1 of drag coefficients CD and an average CL1 of lift coefficients CL in the first segment are equal to or less than 0.225 and 0.180, respectively. An average CD2 of drag coefficients CD and an average CL2 of lift coefficients CL in the second segment are equal to or less than 0.250 and 0.220, respectively. An average CD3 of drag coefficients CD and an average CL3 of lift coefficients CL in the third segment are equal to or greater than 0.260 and 0.220, respectively. An average CD4 of drag coefficients CD and an average CL4 of lift coefficients CL in the fourth segment are equal to or greater than 0.250 and 0.200, respectively.

Abstract: A golf ball 2 has a large number of dimples 10 on a surface thereof. The contours of the dimples 10 are non-circular. A standard deviation of areas of the dimples 10 is equal to or less than 1.7 mm2. A ratio of a total area of the dimples 10 relative to a surface area of a phantom sphere of the golf ball 2 is equal to or greater than 80%. By comparting lines CS obtained by projecting sides of a regular dodecahedron, which is inscribed in the phantom sphere, onto the phantom sphere, a surface of the phantom sphere can be divided into 12 units Ut each of which meets the following mathematical formula (I): ?2?(Nt/12)?Nu?2??(I), where Nt represents the total number of the dimples 10 and Nu represents the number of the dimples 10 on one unit.

Abstract: A golf ball has a large number of dimples on a surface thereof. The golf ball meets the following mathematical formula (I): 1.320?L1?1.420 (I), where L1 represents a ratio of a lift coefficient CL1 which is measured under conditions of a Reynolds number of 1.290×105 and a spin rate of 2820 rpm, relative to a lift coefficient CL2 which is measured under conditions of a Reynolds number of 1.290×105 and a spin rate of 1740 rpm.

Abstract: A golf ball 2 has, on a surface thereof, a dimple pattern consisting of a land 10 and a large number of dimples 8. A process for designing the dimple pattern includes the steps of: (1) randomly arranging a large number of points on the surface of a phantom sphere; (2) calculating a distance between a first point and a second point which is a point closest to the first point; (3) deciding a radius on the basis of the distance; (4) assuming a circle which has a center at the first point and has the radius; and (5) assuming a dimple whose contour coincides with the circle. The dimples 8 are randomly arranged.

Abstract: A golf ball 2 has, on a surface thereof, a dimple pattern consisting of a land 10 and a large number of dimples 8. A process for designing the dimple pattern includes the steps of: (1) randomly arranging a large number of points on the surface of a phantom sphere; (2) calculating a distance between a first point and a second point which is a point closest to the first point; (3) deciding a radius on the basis of the distance; (4) assuming a circle which has a center at the first point and has the radius; and (5) assuming a dimple 8 whose contour coincides with the circle.

Abstract: A golf ball 2 has numerous craters 8 on its surface. The craters 8 are arranged randomly. Of the surface of the golf ball 2, a part other than the craters 8 is a land 10. By the craters 8 and the land 10, a rugged pattern is formed on the golf ball 2. A process for designing the rugged pattern includes the steps of: (1) assuming a plurality of states; (2) assuming a large number of cells on a spherical surface; (3) deciding an initial state of each cell; (4) determining whether or not to change a state of the each cell based on states of a plurality of cells located adjacent to the each cell; (5) updating the state of the each cell based on the determination; and (6) assigning a land 10 or a recess to the each cell according to the state of the each cell.

Abstract: On the basis of a surface shape appearing at a predetermined point moment by moment during rotation of a golf ball having numerous dimples on its surface, a data constellation regarding a parameter dependent on a surface shape of the golf ball is calculated. A preferable parameter is a distance between an axis of the rotation and the surface of the golf ball. Another preferable parameter is a volume of space between a surface of a phantom sphere and the surface of the golf ball. Fourier transformation is performed on the data constellation to obtain a transformed data constellation. On the basis of a peak value and an order of a maximum peak of the transformed data constellation, an aerodynamic characteristic of the golf ball is determined. The peak value and the order of the maximum peak are calculated for each of PH rotation and POP rotation.

Abstract: A golf ball 2 includes a spherical core 4 and a cover 6 positioned outside the core 4. The golf ball 2 further has dimples 8 on a surface thereof. The core 4 is obtained by crosslinking a rubber composition. The difference between a hardness H(5.0) at a point that is located at a distance of 5 mm from the central point of the core 4, and a hardness Ho at the central point is equal to or greater than 6.0. The difference between a hardness H(12.5) at a point that is located at a distance of 12.5 mm from the central point, and the hardness H(5.0) is equal to or less than 4.0. The difference between a hardness Hs at the surface of the core 4 and the hardness H(12.5) is equal to or greater than 10.0. The difference between the hardness Hs and the hardness Ho is equal to or greater than 22.0. There is no zone in which a hardness decreases from the central point to the surface. The rubber composition of the core 4 includes 2-naphthalenethiol. A cross-sectional shape of each dimple 8 is a wave-like curve.

Abstract: A golf ball has a large number of dimples on a surface thereof. The golf ball meets the following mathematical formula (I): Su?9.0*So?6.04??(I), Where: So represents a ratio of a sum of spherical surface areas of all the dimples to a surface area of a phantom sphere of the golf ball; and Su represents a standard deviation (mm2) of the spherical surface areas of all the dimples. Preferably, the ratio So is equal to or greater than 0.780. Preferably, the standard deviation Su is equal to or less than 2.150 mm2. Preferably, a number of the dimples is equal to or greater than 300 but equal to or less than 390. Preferably, an average Sa of the spherical surface areas s of all the dimples is equal to or greater than 14.00 mm2.

Abstract: A cross-sectional shape of each of dimples 8 of a golf ball 2 is a wave-like curve. The wave-like curve has two first curves 14, two second curves 16, two third curves 18, and one fourth curve 20. Each first curve 14 and each third curve 18 are upwardly convex. Each second curve 16 and the fourth curve 20 are downwardly convex. Each first curve 14 is connoted to a land 10 at an edge Ed. Each second curve 16 is connected to the first curve 14 at a first inflexion point 22. Each third curve 18 is connected to the second curve 16 at a second inflexion point 24. The fourth curve 20 is connected to the third curves 18 at third inflexion points 26. In the wave-like curve, the upwardly convex curves 14 and 18 and the downwardly convex curves 16 and 20 are alternately arranged.