Having declined 24% in the last month, it's safe to say that shares of 3D Systems (DDD -5.62%) have taken a bit breather. In this video, Fool contributor Steve Heller talks to Alison Southwick about the situation and shares why he believes setting a long-term view is crucial when investing in high-growth companies like 3D Systems. In particular, he says, high-growth companies are often victims of unrealistic expectations, which can cause shares to swing violently from month to month. Ultimately, he believes 3D Systems is a winner for the patient and strong-stomached investor, given the growth prospects for the total 3-D printing industry in the years to come.