  In this work, a three-quark picture is constructed using a bottom-up approach
for baryons in light-front quark model. The shape parameters, which
characterize the momentum distribution inside a baryon, are determined with the
help of the pole residue of the baryon. The relation between the three-quark
picture and the diquark picture is clarified. When building the model, we find
that Lorentz boost plays a crucial role, and the bottom-up modeling approach
can be generalized to multiquark states. Based on this, a unified theoretical
framework for describing multiquark states may be established. As a by-product
of model construction, we can easily obtain a newly improved definition of
baryon interpolating current. The hadron interpolating currents are the
starting point of Lattice QCD and QCD sum rules, and therefore are of great
importance.
