A 3D printing system can include an extruding system, a curing system, a positioning system, and a feedback system. The extruding system can include a feed pipe coupled to a printing material source and a nozzle having a longitudinal axis along which printing material is extruded. The nozzle can extrude printing material at a printing angle between the longitudinal axis and the top surface of a layer of printing material being printed. The curing system can include light or other curing components configured to cure the printed material after extrusion. The positioning system can include a platform that supports the extruding system and a platform rotating subsystem that rotates the platform during the printing process to adjust the printing angle. The feedback system can include a processor and sensors to detect the location of the nozzle with respect to the 3D printed object or other objects in the printing area during the printing process.