The paper presents a method for projection generation through a 2-D pixel image or a 3-D voxel volume. During the design of the method, we have strived to apply knowledge from signal processing theory. Introductory experiments, were the projection generation method was used in an iterative CT reconstruction loop, indicate that the method is sound. Our hope is that the method could be applied in many different connections, were one task is to compute projections through a 2-D pixel image or a 3-D voxel volume. In the future we plan to do more experiments, both in 2-D and 3-D, which hopefully further demonstrates the usefulness of the method.