1. A method of coding three-dimensional (3D) video data, the method comprising: generating a current list of merging candidates for coding a video block of the 3D video data, wherein a maximum number of merging candidates in the current list of merging candidates is equal to 6, there are 20 possible combinations of list 0 and list 1 motion vectors of different bi-predictive merging candidates in lists of merging candidates having 5 bi-predictive merging candidates, and generating the current list of merging candidates comprises: determining that a number of merging candidates initially in the current list of merging candidates is less than 5, wherein each respective value of a combination index from 0 to 11 corresponds to a respective pre-defined combination of values from 0 to 3; and in response to determining that the number of merging candidates in the current list of merging candidates is less than 5, performing the following for each respective value of the combination index from 0 to 11 until at least one of the following conditions is true: the respective value of the combination index is equal to the number of merging candidates initially in the current list of merging candidates multiplied by one less than the number of merging candidates initially in the current list of merging candidates, and the current list of merging candidates has 6 merging candidates: determining whether a first merging candidate in the current list of merging candidates has a list 0 motion vector and whether a second merging candidate in the current list of merging candidates has a list 1 motion vector, wherein the first merging candidate and the second merging candidate are at positions in the current list of merging candidates indicated by the pre-defined combination of values corresponding to the respective value of the combination index; responsive to determining the first merging candidate has a list 0 motion vector and the second merging candidate has a list 1 motion vector, deriving a respective combined bi-predictive merging candidate, wherein the respective combined bi-predictive merging candidate is a combination of the list 0 motion vector of the first merging candidate and the list 1 motion vector of the second merging candidate, wherein the motion vector of the first merging candidate and the motion vector of the second merging candidate refer to pictures in different reference picture lists; and including the respective combined bi-predictive merging candidate in the current list of merging candidates.