What is HDRI? Learn more about HDR images

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What is HDRI? What does HDRI mean?

An HDRI, which stands for High Dynamic Range Image, is a 360° image that is wrapped around an image or even a 3D model for lighting and background purposes. It is created by mixing several images of the same scene with different exposures (from the darkest shadow to the brightest highlight). To do this, it stores the three color values of the RGB scale with floating point precision, which means that the brightness is recorded in each color pixel. Precisely, this panoramic photo contains 32 bits per pixel per channel, which is much more than the traditional 8-bit JPEG image. In this article you will learn more about high dynamic range imaging, its different lighting uses, how 3D experts use HDR environments and how to apply it to 3D scenes.


A HDR image of a forest used for 3D purposes


What is high dynamic range imaging used for?

Today, high dynamic range imaging is used in many different applications around the world. Below is a list of the most common uses. 

HDRI for 3D visualization and 3D animations

High dynamic range images are commonly used in 3D visualization. Indeed, adding an HDRI environment to a 3D model allows for a detailed and realistic rendering of lighting reflections. Without these features, a 3D model/scene can look cartoonish and less professional. For the same reasons, HDRIs are used for animation interior visualization too.

 Below is an example of a 3D model before and after adding an HDRI environment using Visao’s 3D visualization creation platform.

3d model before hdri image
Before adding an HDRI
After adding an HDRI

HDRI for architect rendering

HDRI environments are commonly used for rendering architectural renderings. These panoramic images, who vary in tone and mood, give a realistic lighting effect on 3D scenes and objects. It also adds more natural light to a scene. In this picture below, you can see the reflection of the HDRI particularly on the architect rendering floor.

3D architecture rendering using hdri

HDRI monitors and TVs

More and more televisions and monitors today offer DisplayHDR 400/600/1000 built into the product. With such a feature, HDR monitors and TVs can display many more shades of color values than ordinary displays. This allows users to see more details (especially dark shadows) and light, for example in video games and movies. This feature makes the display much more realistic.

hdri monitor

HDR Photography

HDR photography is the process of combining several photos (taken at various exposures on a camera) to generate a more detailed and cleaner scene. Sunrises, sunsets, and nightscapes are all common subjects for HDR photos.

hdri picture of a sunset


What is the file format for HDR images?

A HDR file uses the .hdr extension. The file format can be opened on many different 3D modelling softwares such as Adobe Photoshop, Blender and Maya.


How does the HDR file encode data?

A HDR file’s pixel value can include the whole tonal lighting range found in the physical world, not just the RGB range. High dynamic range images have the potential to display the widest variety of pixel values conceivable, from direct light to the deepest shadows. HDR may be created in two ways: by merging different images in a certain way, or by using image sensors using 3D modelling softwares.


What is the difference between HDR and HDR10?

High dynamic range technology is the name given to this technique (HDR). HDR10 is the most basic and widely supported form of the technology. The ST2084 Perception Quantization curve is used in HDR10, which provides for a maximum lighting brightness of 1000 nits. HDR10+, which incorporates dynamic metadata and brightness values up to 4000 nits, provides an even sharper and crisper image quality than normal HDR10.


How to know which high dynamic range environment to pick for a 3D model?

3D experts typically choose an HDRI environment that represents the physical location of the 3D object. However, any HDRI environment can add a unique lighting feature to a 3D model. For example, an HDRI environment of a forest can be applied to the 3D model of a mountain bike to give a more realistic lighting impression of the model. A HDR image of a sky can also be used to give a general realistic view of the object without any specific background.

Why do 3D experts use HDRI instead of LDRI for 3D models?

3D experts use HDR images rather than low dynamic range (LDR) images because it allows them to store much more brightness.

For instance, JPG files, the most common file type for pictures, use a low dynamic range (LDR). This means that it can only contain a small range of brightness, precisely from 0 to 255. This light range is too small to illuminate a 3D object (and its textures) correctly. The 3D model can be left cartoonish and not realistic. In an HDR image, the range of brightness is virtually infinite (full dynamic range), which is why it is used by 3D experts. It allows for more tone and mood.


Where can I find HDR images?

It is possible to create HDR images of basically any picture using popular 3D modelling softwares such as Blender, Maya and Keyshot. It is also possible to get free HDR images online from sites such as  Poly Haven and HDR maps. At Visao, our 3D experts help you choose and apply the best HDR image for your 3D visualizations.


How do you open a HDRI?

Because it employs low dynamic range rendering technology, a standard display will not be able to completely open HDRIs. To read an HDR file on a non-hdr device, you must first convert it to a low dynamic range format. This may be accomplished using a tone operator (tone mapping), which will simulate the look of pictures with a high dynamic range. The HDR image will now be converted to a regular bitmap format.


How do you apply a HDRI image on a 3D model?

It is possible to apply an HDRI image to a 3D model using common 3D modeling software such as Blender and Maya. However, if you are looking for a user-friendly, online way to enhance your 3D model using an HDR image, you can use Visao‘s 3D visualization online platform and create realistic models with a few clicks.

How can you use HDRIs in nXt Render?

HDRIs are used by NXT Render to provide light to environments. These nxt hdri environments can be wrapped around scenes in NXt render. This will give a scene a light direction as well as lighting reflections on different portions of a site plan rendering. In Flamingo nXt, this functionality is also available.


How to convert HDR files (.hdr)?

It is possible to convert GLB files into specific formats. Below is a list of the most common conversions.

How to convert HDR to JPEG

Once you have your HDR file ready, you can use a free online resource that can convert the hdr file in seconds to a JPEG.

How to convert HDR to PNG

Once you have your HDR file ready, you can use a free online resource that can convert the hdr file in seconds to a PNG.


Need help with HDRI environments for 3D visuals?

Visao provides a web-based platform that allows manufacturers to use their CAD files to create interactive 3D visualizations of their products for marketing, sales processes, trade shows and production.

Do you need additional details or even custom recommendations for producing photorealistic 3D models of your industrial designs? Contact us and we’ll be happy to help you with the process!