11. A processor-implemented method for modeling a pose of a hand of a user, comprising: obtaining depth pixels of the hand in one or more frames; processing the depth pixels of the one or more frames to identify articulated portions of the hand; accessing a model of the articulated portions of the hand, the articulated portions of the hand of the model comprising a palm and fingers, including finger segments; matching the articulated portions of the hand of the model to the identified articulated portions of the hand of the depth pixels of the one or more frames, to provide an initial match; evaluating an extent to which distance constraints are violated in the initial match by at least one of the fingers, the distance constraints comprise constraints on distances between finger segments of the at least one of the fingers; rasterizing the model to provide depth pixels of the model; comparing the depth pixels of the at least one of the fingers to the depth pixels of the one or more frames to identify, from among the depth pixels of the one or more frames, non-overlapping depth pixels of the one or more frames which are not overlapping in at least one comparison plane with the depth pixels of the at least one of the fingers of the model; and adjusting the model: (a) in an attempt to satisfy the distance constraints, including adjusting a length of at least one finger segments of at least one of the fingers of the model based on the extent to which the distance constraints are violated by the at least one of the fingers, and (b) based on the comparing, to cause the model to more closely match the non-overlapping depth pixels of the one or more frames, by increasing a width of the at least one of the finger segments of the at least one of the fingers of the model.
13. The processor-implemented method of claim 11 , further comprising: comparing the depth pixels of at least one of the articulated portions of the hand, other than the at least one of the fingers, to the depth pixels of the one or more frames to identify, from among the depth pixels of the one or more frames, non-overlapping depth pixels of the at least one of the articulated portions of the hand of the model which are not overlapping in the at least one comparison plane with the depth pixels of the one or more frames; and adjusting the model based on the comparing of the depth pixels of the at least one of the articulated portions of the hand, other than the at least one of the fingers, to the depth pixels of the one or more frames, to cause the model to more closely match the depth pixels of the one or more frames, by decreasing a width of the at least one of the articulated portions of the hand of the model.