donaldson-thomas (dt) theory is an enumerative theory which produces a virtual count of stable coherent sheaves on a calabi-yau 3-fold. motivic donaldson-thomas theory, originally introduced by kontsevich-soibelman, is a categorification of the dt theory. this categorification contains more refined information of the moduli space. in this talk, i will explain the role of d-critical locus structure in the definition of motivic dt invariant, following the definition by bussi-joyce-meinhardt. i will also discuss results on this structure on the hilbert schemes of zero dimensional subschemes on local toric calabi-yau threefolds. this is based on joint works with sheldon katz. the results have substantial overlap with recent work by ricolfi-savvas, but techniques used here are different.