3D Systems Corporation (DDD) has lowered its 2014 earnings guidance dramatically due to falling margins and unexpected investment activity causing analysts to drop its 2014 price target, but there could still be solid buying opportunities if the market overreacts. 3D Systems revenue strong, but margins miss expectation “This seems to be something of a trend in the 3D space; revenue surprising to the upside, but margins trailing off a bit relative to expectations,” writes J.P. Morgan analyst Paul Coster, who rated DDD as Neutral and reduced his price target to $54 from $67. DDD is currently trading at $62.10, down…