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Tag Archive for: hdri

Making of METEORA by Santi Sánchez, showcasing Megascans

Making of METEORA

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Tresde’s Santi Sánchez is no stranger to the blog, with two great articles attributed to him here – Making of IRACEMA in the Dusk & Making of Crystal Box Villa. This time he took Quixel’s Megascans for a serious spin while creating METEORA, a personal concept design project based on a volcanic vivarium pavilion, developed with the intention to use Megascans 3d models as hero characters and study the use of this software + content library combo in an ArchVIZ context.

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PETER GUTHRIE HDRI Skies Submitted Image Winner / Maciej Kozlowski

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Congratulations to Maciej Kozlowski for winning the second stage of the August 2014 PETER GUTHRIE HDRi Skies giveaway! During the month of August I held that giveaway and the first winner was randomly selected from all who commented in the original PETER GUTHRIE HDRi Skies giveaway post. Maciej’s architectural subject and coastal location were blended very well with Peter’s 1044 Overcast HDRi Sky, resulting in a beautifully moody and compelling visual which awards him a complete set of 45 skies from Series No. 1! Big thanks to Peter Guthrie for sponsoring this giveaway and to all who took part in it… see you in the next one!

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Tag Archive for: hdri

10 Free HDRi Spherical Skies Maps

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10 Free HDRI Spherical Skies Maps


And an introduction to Image Based Lighting in Architectural Visualization using HDRI Skies. For the full commercial version of this free pack, visit Viz-People HDRi V1 Page.


Download Your Free HDRI Pack

The ARCHVIZ 2022 Black Friday is live with great HDRI deals and more! Check it out now.

What is an HDRI Sky?

An HDRI Sky (High Dynamic Range Image) in the context of Architectural Visualization is 360 Spherical Sky photograph that was taken to cover the entire field of vision and contains significantly more lighting information in it that is ideal for emitting light inside a computer-generated scene.

“HDRI” stands for High Dynamic Range Image. “Dynamic range” is the measurement of how much brightness information is contained in an image, so a “high dynamic range” image is an image that has a very large range of brightness, more than you can see on your screen in one go actually.

Most photos and images, in general, are what I call “LDR” images or Low Dynamic Range images. They store 8 bits of data for each of the red, green and blue channels for every pixel. An example of an LDR image is a JPG file.

The problem with LDR images is that they are limited to a relatively small range of brightness, from 0 to 255, which is not actually all that much.

If you want to light a 3D scene using an image, what you really need is a format that can store more than just 8 bits of data per channel so that you can have a much larger range of brightness. Luckily, there are several formats that can do this, the most common of which has the extension “.hdr”.

Generally speaking, an HDRI (High Dynamic Range Image) is simply an image that contains more than 8 bits of data per pixel per channel. Image formats like JPG and PNG are typically 8-bit and are sometimes referred to as ‘LDR’ (Low Dynamic Range) images, whereas image formats like EXR and HDR store more data and are therefore HDRIs.

However, in the CG world, we have come to use the term ‘HDRI’ to describe a 32-bit 360°x180° equirectangular image that is used for lighting CG scenes.

HDRIs are often used as the only light source in order to create a very realistically lit scene or to match the lighting from video footage (using an HDRI shot on the same set as the video was taken). But of course, they are also used to complement standard lighting techniques and to add detail to reflections.

It really doesn’t matter which, people generally understand you either way. But if you want something to boast to your English teacher about, ‘HDR’ stands for ‘High Dynamic Range’, and the ‘I’ at the end stands for ‘Image’…

So you cannot say ‘This is an HDR’ because ‘high dynamic range’ is one big adjective without a noun. But you can say ‘This is an HDRI’ because ‘image’ is the noun that is being described as ‘high dynamic range’. You can also say ‘This is an HDR image’, or ‘This is an HDR panorama’, as long as there’s a noun after it.

But like I said, it doesn’t really matter. ‘HDR’ and ‘HDRI’ are both commonly used as nouns that mean the same thing.

The number of EVs (or ‘stops’) is based purely on the number of brackets captured. For example, 12 EVs means 5 photos were taken with 3 EVs between them (shutter speeds: 1/4000, 1/500, 1/60 1/8, 1″), and since there are 4 gaps of 3 EVs between them, the dynamic range is said to be 12 EVs (4×3=12).

Unfortunately, there is no standardized way for measuring the dynamic range of an HDRI. Different people use different methods, so there’s no reliable way that you as a customer can tell whether website-A that claims 50 EVs of dynamic range is actually better than website-B that has 20 EVs.

The main thing to look out for is whether an HDRI is unclipped or not. They usually don’t mention anything if it is indeed clipped, so watch out. Being unclipped means the full range of brightness in the scene was captured, including the super crazy bright sunshine. If an HDRI is clipped (aka “clamped”), it will produce unrealistic lighting which is usually flat and lacking contrast.

HDRI is a much higher dynamic range of color and values than traditional bitmap formats. Instead of encoding colors like a computer monitor, using 24-bits of color for each pixel, HDRI is modeled after trichromatic base of the human eye and store actual luminance values in each pixel. So not only is color contained but the strength and brightness of the light at that point in the map. The range of color and light that can be contained in this format is much greater than the RGB scale of traditional computer graphics. nXt uses HDRI values throughout the rendering process, putting nXt into the classification of HDRR (High Dynamic Range Rendering)

In HDRI, each channel holds more accurate values. For instance, if you look at a 60 watt light bulb, it will be white. But if you look at the sun it is also white, but 10,000 times brighter. If you look at a star in the night sky, it is also white, but may be 1,000 times dimmer than the light bulb. In RGB, white is white, in HDRI, light has a much greater range and can capture the actual amount of light coming from each of these sources.

There is no easier or quicker way to light a CG scene than to use an HDRI. They are essentially snapshots of the real world that contain exquisitely detailed lighting information, which can transport your bland CG objects into realistic virtual environments.

Not only do they provide accurate lighting, but they can be seen in the background and in reflections, which makes them all the more immersive.

need some videos here for each software. Mainly SketchUp, Cinema 4D and 3dsmax.

Creating an HDRI

There are various ways to make an HDRI, but it’d be impossible to cover every detail so I’ll show you a method that gives you decent results with a reasonable amount of effort.

The Gear you will need:

  • DSLR camera
  • Wide angle lens (less than 20mm)
  • Tripod
  • Panoramic head (optional, but highly recommended)

The Software you will need:

  • Magic Lantern (free) – firmware for Canon cameras, skip if you have a different brand of course.
  • PTGui Pro (€149) – to stitch the HDRI together.

There is a sort of free alternative to PTGui called Hugin, but in my experience, it really isn’t usable for this sort of panorama. While you may be able to spend a few days hacking at Hugin to get it to work for you, remember that you’ve already spent a few hundred bucks on camera equipment so a little extra on software that will save you time is a good investment.

Recommended HDRi Products

The following HDRi products are the ones I use myself and I feel very confident recommending them to you. Enjoy!

Peter Guthrie HDRi Skies Shop


PETER GUTHRIE HDRI SKIES SHOP

Get Peter’s HDRi Skies

VIZPARK HDRI Collection



Get VIZPARK HDRIs

Viz-People HDRI & Skies



Get Viz-People HDRI & Skies

Mediterranean Light



Get Mediterranean Light

darstellungsart.skies



Get darstellungsart.skies