Three-dimensional shoe

1. A three-dimensionally knitted upper for an article of footwear comprising:

at least one activated shrink yarn;

a first region comprising a first number of knitted layers, wherein the first region is a bottom portion of the knitted upper, and wherein the bottom portion is configured to attach to a sole of the article of footwear; and

a second region comprising a second number of knitted layers, wherein the second region is an upper portion of the knitted upper,

wherein the second number of knitted layers is greater than the first number of knitted layers, and

wherein the knitted upper is a single piece.

2. The knitted upper according to claim 1 , wherein the at least one activated shrink yarn comprises at least one air-tack yarn.

3. The knitted upper according to claim 1 , wherein the at least one activated shrink yarn is arranged in at least one of a heel portion of the knitted upper, a toe portion of the knitted upper, and the heel portion and the toe portion of the knitted upper.

4. The knitted upper according to claim 1 , further comprising:

at least one melted fuse yarn.

5. The knitted upper according to claim 1 , wherein the knitted upper is essentially seamless.

6. The knitted upper according to claim 1 , wherein the knitted upper further comprises:

at least a first yarn; and

at least a second yarn,

wherein a number of plies of the second yarn is greater than a number of plies of the first yarn.

7. The knitted upper according to claim 1 , wherein the first region comprises one knitted layer and the second region comprises two knitted layers.

8. A shoe, comprising:

a knitted upper according to claim 1 ; and

a sole.

9. A method of producing a knitted upper for an article of footwear, the method comprising:

knitting at least one activatable shrink yarn into at least one of a heel region and a toe region of the knitted upper;

knitting a first region of the knitted upper comprising a first number of knitted layers;

knitting a second region of the knitted upper comprising a second number of knitted layers, wherein the second number of knitted layers is greater than the first number of knitted layers;

knitting the knitted upper essentially as a single piece in a three-dimensional knitting process;

arranging the knitted upper on a shoe last; and

activating the at least one activatable shrink yarn such that the knitted upper shrinks to take the form of the shoe last.

10. The method according to claim 9 , wherein activating the at least one activatable shrink yarn comprises heating the knitted upper by applying to the knitted upper saturated steam at a pressure between 1 bar and 5 bar for a time interval between 10 seconds and 20 seconds.

11. The method according to claim 9 , wherein an area comprising the at least one activatable shrink yarn has an area shrinkage of at least 15% under application of saturated water steam at a pressure of 2 bar for 20 seconds.

12. The method according to claim 9 , further comprising:

knitting at least one fuse yarn into the knitted upper.

13. The method according to claim 9 , wherein the knitted upper is knitted on a flatbed knitting machine comprising at least two needle beds.

14. The method according to claim 13 , wherein during the knitting, there is a transfer of the yarns from a first needle bed to a second needle bed when changing a knitting stroke direction,

wherein the transfer defines, on the knitted upper, a parting line, and

wherein the parting line is arranged between a bottom region and a top region of the knitted upper.

15. The method according to claim 9 , wherein the first region and the second region are knitted substantially simultaneously.

16. The method according to claim 13 , wherein the knitted upper is knitted on the at least two needle beds to form a tubular knitted structure to create an essentially seamless knitted upper.

17. The method according to claim 9 , wherein the shoe last is at least partially based on a customized model of an athlete's foot.

18. The knitted upper according to claim 1 , wherein the knitted layers of the second region are connected.

19. The method according to claim 9 , further comprising:

connecting the knitted layers of the second region.

20. The knitted upper according to claim 1 , wherein the second region further comprises a Jacquard knit portion.