In fact the dynamic range is the difference between the darkest and the brightest pixel in your image. For example a HDRI map of a sunny environment, should have a very high dynamic range if you want the reflections and lighting to match the actual real life environment. The sun is ultra bright, and the darker regions (shadows) are very dark. In fact it is impossible with todays cameras to completely capture the dynamic range of a sunny scene. Even with the shortest exposure time, and smallest apertures, the sun will still be an overexposed point in your image (while the rest of your image will be black!).
![]() What is the dynamic range of a HDRI map?![]()
This tutorial covers setting up an HDRI environment in 3ds Max with V-Ray. Next, scroll down the Material/Map Browser list on the left until you find VRayHDRI. This Beautiful 3d model, is a courtesy by Erick who shared exclusively for us, his 3d model done in sketchup 2015, and rendered with vray 2.0, but available in sketchup 8, complete with all textures and some maps, vray Proxies materials and the Hdri used in this scene.
Many HDRI maps you can find on the web, don't capture the full dynamic range present in the real scene. Here's a comparison between 2 HDRI maps, both lowered in exposure equally:
A good hdri map will keep the light sources bright when lowering exposure, while all other pixels will go darker and darker. But as you can see in the bottom row, already after lowering exposure by two stops, the sun in the hdri starts to go from bright white to light grey...
Note the two bands of sun color in the middle. The top HDRI captures a lot more of the actual dynamic range. Only after lowering exposure by 12 full stops(!!!), the sun starts to change its intensity. Lowering the bottom hdri 12 stops results in a black sun color...
![]() Comments are closed.
|
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
December 2022
Categories |