No, for thermal radiation to travel away from a body in a particular direction, it is not necessary to have a colder body along that direction. Thermal radiation can propagate in a vacuum or through transparent media such as air or glass.
Thermal radiation is emitted by any object with a temperature above absolute zero. It consists of electromagnetic waves, including infrared radiation, and it propagates in all directions away from the source. The rate at which thermal radiation is emitted depends on the temperature and emissivity of the object.
The direction of thermal radiation is determined by the geometry and surface characteristics of the emitting object. It radiates equally in all directions, but the intensity of radiation in a specific direction can vary depending on factors such as the shape and orientation of the object.
While a colder body can absorb or reflect thermal radiation, it is not a requirement for the radiation to travel in a particular direction. Thermal radiation will continue to propagate in all directions as long as there is no obstruction or absorption by other objects in its path.