For example, the sky is usually much brighter than the rest of the image therefore toning program will choose to use a darker exposure for the sky and a brighter exposure for the rest of the scene to balance it. HDR is a type of image that is best described as ‘tonal image.’ The idea is to take a few photos with different exposures, and put them together so that all of the images are properly displayed in terms of brightness (not too bright and not too dark). You also need to debunk the myth with the understanding of HDR pictures. You can see in the chrome ball on the back side of that JPG and HDRI appear to be identical, but the light they create is totally different due to the fact that the HDR file stores the correct brightness of the sun and JPG is limited to a range of up to 255 colors, which is too low to provide enough lighting. The difference is even more apparent when we use an example that has even more bright light source like the sun: Here’s a simple scene, illuminated by a JPG and HDRI:Īs you can see, JPG gives flat and unrealistic lighting, while HDRI gives good sharp shadows and lots of juicy contrast, as from the bright fluorescent lights. This means that when you use the image to light up the 3D scenes, the lamp will emit more light. It knows that the lamp’s light is much brighter than the rectangular area around it, but it is only one solid color in the JPG’s version. HDR file retains the brightness of bulb correctly.
The maximum brightness in HDRI is practically infinite that simulates the fluorescent lamps, so they remain visible even if the image is darkened. This is because the maximum brightness of the pixel in the JPG image is 255. Therefore, you need to choose the HDR format.Īll we need to do is play with the brightness to illustrate the difference between JPG and HDR fileĪs you can see, JPG on the left has absolutely no details in the bright areas.
The problem with the LDR image that it is limited to a relatively small range of luminance values from 0 to 255, which is insufficient for the illumination in 3D. They store 8 bits of data for each of the red, green, and blue channels for each pixel. I call the most part of the photos and pictures as LDR images or pictures with a low dynamic range. “Dynamic range” is the amount of data about the brightness of the image such data is the much larger amount of the information than the human eye is able to catch. For example, the use of an incorrect focal distance or a slow shutter speed. Creating high-quality HDRI from scratch is a difficult task that requires very specific equipment and meticulous attitude to the entire process. The easiest way to light a scene in the CG is the use of HDRI.
HDRI is a panoramic photo, which covers all angles from a single point and contains a large amount of data (usually 32 bits per pixel per channel), which can be used for the illumination of CG scene.Ī simple 3D scene, which was lighted only with HDRI:
PORTALIGHT AND HDRI IN VRAY 3DS MAX HOW TO
The second part will be provided in the upcoming days and will describe step-by-step instructions on how to create the HDRI. This article describes the basic concepts and the necessary equipment to create own HDRI.
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