Why use an HDRI over a JPEG in a 3D renderer?

If you are a 3D designer, photographer, or photo editor, you may be familiar with the term HDRI. Most designers and 3D visualizers use HDRI images because they create stunning results. Now, you must be wondering what this term is. Is it an image file format? Is it a photo editing technique? Or is it something else?

If you are a photo editor or 3D visualizer, it is important to know what HDRI is. So, that’s what we will be learning in this article! Here, we will learn in detail:

• What is an HDRI image?
• What is a JPEG image?
• Why do 3D experts use HDRI instead of JPEG for 3D render images?
• Industries that use HDRI over JPEG

Let’s begin!

What is an HDRI image?

HDRI (High Dynamic Range Imaging) refers to the technique of capturing and representing a high dynamic range of lighting information in a digital image. It is done for the purpose of lighting and improving the quality of renderings. HDRI is created by combining several layers of images with various exposures, i.e., from dark to bright images.

In simple terms, HDRI is a technique where images of multiple exposures are blended to bring out details hidden in the shadows or highlights of an image.

HDRI is often used in 3D rendering as it simplifies the lighting process, allowing the designers to get lighting effects that appear natural to the human eye. After HDRI, they can rotate and scale the image, so the lighting for the entire scene is quickly completed.

Used for: HDRI files are used to store photographic imagery containing more detail than traditional photos. In traditional photos, the limited dynamic range causes a lack of detail in the shadows or highlights. HDRI allows photo editors to brighten the corners to create a more natural-looking image.

Other terms: The term HDRI is often combined with three other terms: HDRI map, HDRI environment, and HDRI sky.

• HDRI map: refers to the 360° image that captures all the information necessary to light up a scene.
• HDRI environment: refers to the 360° panoramic image that is wrapped around an image or digital model to add background or lighting. It is often used to make 3D rendered images. It captures the lighting information of a real-world environment to provide realistic lighting and reflections in a 3D scene.
• HDRI sky: falls under the HDRI environment and focuses on the part of the image that represents the sky. It is a simple sky representation that captures its lighting information, colors, and gradients and is made using a cubemap texture.

What is a JPEG?

JPEG stands for Joint Photographic Expert Group. It is a popular image format for storing photographs and uses file extensions like.jpg and.jpeg. It reduces the size of images so that web browsers and photo editing software can support them.

However, it is a lossy compression method where you lose some information when saving images and photos in the JPEG format. It means that some data is removed during compression and can’t be restored to its original form after decompression. The amount of data removed during compression, however, depends on the quality setting. If the quality setting is high, less compression is applied, and the resulting file size will be large.

The main benefit of the JPEG file format is that it compresses photos and images into small file sizes, enabling easy storage and faster file-sharing speeds.

Why do 3D experts use HDRI instead of JPEG for 3D render images?

Usually, 3D artists prefer using HDRI over JPEG as it lets them create high-quality renders of 3D scenes and models. This is because HDRI formats can store more visual information, unlike LDR formats like JPEG, PNG, etc. Let us now discuss in detail why HDRI is preferred over the JPEG format for 3D rendering.

1. Function

   The main function of HDRI is to capture and represent lighting, color, and other visual information from real-world scenes in as much detail as possible.

   The main function of JPEG, on the other hand, is to compress images and photo files.

2. Dynamic range

   HDRI captures and represents a broad, dynamic range of lighting information in a single image. This means that it records and stores luminance values in a way that brings out the details hidden in the brightest highlights and the darkest shadows of a scene.

   The information about lighting conditions stored in HDRI images is used in various 3D rendering techniques to achieve realistic lighting and reflections.

   The JPEG format, however, stores a limited dynamic range containing subsets of color and brightness information. It is used for photographs that do not need a high dynamic range. Unlike HDRI files, JPEGs can’t preserve sharp edges, smooth gradients, solid colors, transparency, or animation.

3. Realism

   HDRI performs a unique optimization of lighting and increases the brightness to show more details in the images. This offers higher image quality and a significant amount of color accuracy, especially when used in high-contrast scenes. Thus, HDRI images can help achieve high realism during 3D rendering.

   As JPEG is a lossy compression method, some image details are lost. Even though they are suitable for storing photographs, they may result in some distortion when used repeatedly in computer graphics or photo editing.

4. Image bit depth

   The HDRI format stores each pixel as a 32-bit value, meaning the maximum pixel brightness goes from 255 to 2,147,483,647. This file format can store brightness and light values that extend beyond the RGB space.

   As they capture the whole tonal range of real-world scenes, HDRIs are often called "scene-referred.” Traditional digital images, on the other hand, are "device-referred" or "output-referred."

   Most pictures captured with modern DSLRs are in the JPEG format. They are also called LDR images as they have a low image bit depth. This format uses an 8-bit value for each of the RGB spaces. One of the major problems with JPEG is that it has a small range of luminance values that are not sufficient to illuminate a scene in 3D rendering.

5. File format

   HDRI images are usually saved in specific 2D file formats that store the pixel value of the image either in 32-bit or 16-bit formats (for editing purposes). The common file extensions used for HDRI images are .hdr, .exr, and .pfm.

   JPEG images usually use the file extensions .jpg or .jpeg. JPEG is a common file format for photos or other image files supported by websites and photo editing software.

6. Imaging flexibility

   HDRI images offer high flexibility during editing and post-processing as they contain a wide range of lighting and color values.

   When saving photos and images as JPEGs, they undergo image compression, offering limited flexibility. Because JPEG files lose image quality when edited repeatedly, it results in the degradation of the image.

7. Applications

   The HDRI format is widely used in 3D rendering, 3D modeling, computer-generated graphics, and 3D simulations to achieve realistic lighting and reflection in scenes.

   Photographers, photo editors, graphic designers, and others primarily use the JPEG format to store photographs, web graphics, and other general images or for file sharing.

Industries that use HDRI over JPEG

Now that you have understood why HDRI is preferred over JPEG for 3D rendering, let us learn about some other industries that prefer HDRI images.

• Architecture

  Creating an HDRI environment is crucial for 3D architectural renderings. For example, designers create panoramic images of interior designs that have varying tones and moods. This helps them achieve a natural lighting effect in 3D scenes and objects.

• Animation

  HDRIs are commonly used in 3D visualization and animation. This file format allows 3D artists to achieve a detailed and realistic rendering of the shadows, reflections, and lighting for their 3D models. Such realistic effects make 3D animations look more professional and less cartoonish.

• Gaming

  Advancements in technology have resulted in the creation of high-resolution 4K displays and high dynamic range (HDR) technology. HDR displays offer a wider dynamic range and color accuracy. They use better contrast, vivid colors, and greater light, shadow, and color detail to improve the visual experience.

  It has encouraged the gaming industry to leverage this visual technology to create high-quality video games that users can experience on HDR displays. Game developers are using HDRI technology for:

  • Realistic lighting,
  • Enhanced visuals,
  • Dynamic weather and time of day,
  • Improved reflections,
  • High-quality textures,
  • Post-processing effects,
  • Artistic expression,
  • Virtual reality (VR) and augmented reality (AR), and
  • Cinematic cutscenes

• Automotive industry

  Most car companies leverage HDRI technology in virtual production, where they photograph their vehicles in real-world environments without taking the car to the location. That is because it is much cheaper and easier to send photographers to create background images and HDRI maps for use in CGI locations.

  They use HDRI to add realistic lighting and reflections to vehicle details and interior shots.

• Virtual reality

  As technology advances, people are looking for more immersive and hyper-realistic ways to experience their virtual surroundings. Here is where image exposure plays a major role in creating a realistic virtual environment. With HDRI, VR developers can create high-quality textures and offer a realistic and believable virtual world to users.

Conclusion

With the constant evolution of 3D technology, industries are trying to achieve more realism in their 3D assets. In recent years, HDRI has become more prolific as it offers a simpler way for 3D artists to achieve visually stunning and realistic lighting and reflective effects. That is why more 3D visualizers choose HDRI for realistic 3D rendering.

We hope this comprehensive comparison of the HDRI and JPEG file formats has given you a better understanding of the differences and the various benefits of HDRI over JPEG.

If you want to create photorealistic renders of your 3D models, get in touch with 3D rendering companies that deliver high-quality, realistic visuals.

Start exploring HDRI imaging technology today! Good Luck!

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