The powder compaction modeling of advanced sintering techniques such as spark plasma sintering is a crucial step in the conception of complex shape objects and the understanding of the process. The complete identification of common powder compaction models requires lengthy experimental investigations based on creep and compaction tests. In order to circumvent this problem, a semi-theoretical approach can be employed whereby the mechanical behavior of the powder material is determined theoretically and the temperature-dependent equivalent creep behavior of the material is determined experimentally. Extending the use of this approach to polymers, metals and ceramics is discussed and compared to other independent methods.