To simulate HDR lighting in RS without HDR images
by David Coombes
If taking a scene, take a photo from a tripod at one exposure, than at a shorter exposure to catch the details in the highlights, giving you two pictures.
Then to map this image to an object, create a VSL material with two texture
highlights = Texture(coords) : Shorter exposure pic
highlights *= (10,10,10) : Multiplier for bright spots. Crank as high as
Illumination = Texture(coords) : Normal photo
Illumination += highlights : Add the highlights on top
Of course I wasn't using HDR lighting as RS didn't have GI back then, but in
reflections this produced dynamic highlights not possible with conventional
images. I also took an existing photo, changed the brightness/contrast so
only highlights were kept and blurred these a bit, to add these as the
highlights. Worked very well for a 'skylight' in a room.
It may not be mathematically correct HDR but it has the same results such
that the eye doesn't notice it's wrong.