What is HDRI and its use in 3D creation?

If you are a 3D artist or designer, you have probably heard about HDRI. Do you wonder what does HDRI mean?

In this article, iRender will explore what is HDRI and its use in 3D creation.

HDRI is short for High Dynamic Range Image. But what does this term mean?

Let’s say you take a selfie on your phone or see a random photo on the internet. Each pixel of the photo is represented by a color and a brightness value. The brightness values range from 0 to 255 (which is also the maximum brightness that a computer can display). The dynamic range of an image refers to that range of brightness values. It helps you to see the photo on your phone or computer screen. In the real world, however, brightness values vary a far wider range of levels than 0 – 255. In reality, the light could be thousands or millions of times brighter.

As a result, HDRI images are created to address this issue. They have an extensive enough brightness value range to store real-world brightness values. So, when a photographer takes an HDRI image, he captures all the lighting information about a scene in an HDRI image, which is much more than a traditional photo. Every pixel in an HDRI image contains more levels of lighting data than what is shown on the screen.

Image: CGI.Backgrounds

Other than HDRI images, you may come across terms such as HDRI map, HDRI environment, or HDRI sky. They all are digital photographic scans of locations, although the locations vary.

• HDRI map is generally 360-degree photos of real-world locations with high dynamic range lighting data.
• HDRI environment typically refers to an HDRI map of immersive places, such as the interior of a race track, a building’s courtyard, or a vividly lighted warehouse interior.
• HDRI sky / HDRI dome is often an HDRI Map of an outdoor site with a large open sky.

From the above, we know that most phone and computer screens can only display a restricted range of brightness values (0 – 255). So what is the purpose of the high dynamic range lighting data in an HDRI map?

Well, HDRI is a very powerful tool when it comes to 3D rendering. In other words, HDRI is used for image-based lighting in 3D software.

3D artists and designers need all the lighting data in an HDRI map to light their 3D models or scenes accurately. When you light a 3D scene with an HDRI map, the lighting and reflections from the HDRI map surround the 3D objects in the background. The HDRI map offers accurate lighting and reflection values for the 3D models once you render them with materials. As a result, the render appears to be a photograph of the 3D model taken at the real location.

Image: Greyscalegorilla

To sum up, using HDRI maps is an easy-to-use lighting technique that will allow you to produce photorealistic renders in a short amount of time. It is useful for achieving the ideal look for any mood or time of day. Indeed, artists and designers take advantage of HDRI maps for a wide range of industries.

• Automotive rendering.
• Product rendering.
• Architectural visualization.
• Motion design.
• and many more.

So you know what is HDRI and its use in 3D creation. Using an HDRI map is similar to applying a texture on environment light. HDRI images can be stored in a variety of formats. The two most common are OpenEXR (.exr) and Radiance RGBE (.hdr). Moreover, it is compatible with many 3D rendering software.

Instead of changing lighting manually, HDRI allows 3D designers and artists to focus on telling their stories through images. It also enables designers to quickly adjust a scene without wasting hours on updating the lighting values.

What about the final rendering? Is it possible to send a scene with HDRI to the online render farms? With iRender Farm, it is like a piece of cake. Since we provide remote servers, you work on our powerful machines as if you were using your own computer. So, you transfer your projects with HDRI to iRender, then render as usual but many times faster. It is just easy as that.

Try iRender Farm now. Not only do you save your creating time with HDRI but you also save your time with our next level of rendering speed.