Some examples include methods of operating an additive manufacturing machine including generating thermal energy with a thermic source including a warming source and a fusing source, each of the warming and fusing sources having a major axis longitudinally extending in a y-axial direction above a build zone, the build zone to contain a build material and a fusing agent, moving the thermic source in a x-axial direction orthogonal to the y-axial direction over the build zone at a constant velocity, delivering a first substantially uniform heat flux from the warming source and a second substantially uniform heat flux from the fusing source to cause portions of the build material that the fusing agent is disposed on to form a layer of a three dimensional object, and continuously generating thermic energy from the thermic source during a build process of the three dimensional object.