First, we study a new tip of unit speed associated curves in the E3 like a normal-direction curve and normal-donor curve. Then we achieve qualification for these curves. Moreover, we confer applications of normal-direction to some special curves such as helix, slant helix, plane curve or normal-direction (ND)-normal curves in E3. And, we show that slant helices and rectifying curves might be assemble by using normal-direction curves.