INTERACTIVE BUILD PLATE

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for tracking object movement within a three-dimensional workspace. A method includes receiving, by a controller, break beam sensor data indicating object detection by a break beam sensor of a plurality of break beam sensors configured to detect objects within the workspace. The method includes receiving plate sensor data indicating object detection by a plate sensor of a plurality of plate sensors configured to detect objects resting on a surface of a plate defining a floor of the workspace. The method includes determining that an object passed through the workspace to rest at a position on the surface; comparing the position of the object to a target position of the object; and in response to determining that the position of the object does not satisfy similarity criteria for matching the target position, performing one or more actions.