Additive manufacturing systems with standoff distance monitoring and control, which can be responsive, dynamic, and in real-time. These technologies can use a standoff distance measurement system to real-time monitor, read, or interrogate a workpiece or a substrate on which the workpiece is positioned, as the workpiece is moved past a directed energy source, or vice versa. These technologies can use a feedback controller to responsively and dynamically control the standoff distance in real-time based on data from the standoff distance measurement system.