The disclosure notably relates to a computer-implemented method for forming a dataset. The dataset is configured for learning a function. The function takes as inputs images of instances of one or more classes of real objects. The method comprises, for each class, providing a parametric model of the class, generating a plurality of 3D modeled objects with the parametric model, and adding to the dataset, for each one of the plurality of 3D modeled objects, one or more corresponding images. The generating includes traversing one or more of the set of ranges. The method constitutes an improved solution for forming a dataset configured for learning a function.