Dimensional physics (DP) is a theory that unites general relativity (GR) with quantum field theory (QFT). The QFT results, via a common basis in spacetime, from the GR as a correspondence principle. This requires assumptions about the structure of spacetime. There are different spacetimes and each is continuous. The number of space dimensions separates them from each other. The "dimensionaltransition" creates the quantisation. Any form of energy or mass is a spacetime density directly in spacetime. Gravity is a spacetime strain directly in spacetime. A density creates a stretch. Therefore, all "objects and forces" are changes in spacetime itself. There are no separate objects using spacetime as a "stage". Different spacetimes are not only a dynamic stage, they are the only actors. The various manifestations of the elementary particles of the Standard Model, are a combination of low-dimensional spacetime densities. The proposed solution in the DP is thus a geometric approach.