1. A method for adapting a 3D model of an object, comprising the steps of: performing, via a processor, at least one projection of the 3D model to obtain at least one 2D image model projection with associated depth information; performing, via the processor, at least one state extraction operation on the at least one 2D image model projection to obtain at least one state comprising a configuration of object features, the features being represented by a set of values; either receiving, via the processor, external state information being offline determined state information based on 2D still image data or on descriptive information, or receiving, via the processor, an external 2D image input, from which the external state information is extracted; determining, via the processor, a target state from the at least one state and from the external state information by performing a weighted combination of the at least one state and the external state information with the weights reflecting confidences of the states determined during the state extraction; adapting, via the processor, the at least one 2D image model projection and the associated depth information using the at least one state and the target state to obtain at least one adapted 2D image model and an associated adapted depth; and back-projecting, via the processor, the at least one adapted 2D image model to 3D based on the associated adapted depth to obtain an adapted 3D model.