About High Dynamic Range Images (HDRI)
High Dynamic Range Images (HDRIs), if used for lighting, greatly improve the quality of renderings. HDRI are images that use the pixel color value of the image as light sources, and are therefore also called image based lighting. This renders images as they would appear in the real-world environment. HDRIs do not require any external light sources for rendering lighting effects and are quick to setup unlike direct lighting like spot, distant or lightbulb type of lights.
HDRIs can be used as sources of lighting, backgrounds, and for model reflections. HDRIs can also be used as a source for model reflections in the
Shading With Reflections (Enhanced Realism) mode.
Creo supports only the Spherical HDRI. If you use any other map type, Creo loads the file, but renders the HDRI as a spherical map. The rendering may not be as desired.