Alec-HDRI Lighting

One of the things Alec pointed out, when creating my assets, was to use an HDRI lighting set up in Maya, to reflect real life reflections on my objects.

garage_1k

garage

An example of an HDRI and the effect it has on different materials.

What are HDRI’s

HDRI’s are snapshots of the real world lighting, giving intensely detailed information, giving rise to more realistic virtual environments.  The not only provide accurate lighting, but can be seen in the background and in reflections

NCreating a high quality HDRI from scratch is quite a complicated task that requires very specific equipment and a meticulous workflow. One mistake like using the wrong focal length or choosing a slow shutter speed can mean all your time has been wasted and you’ll have to start all over again.

I’ve been making HDRIs for a couple of years now, so I hope I can save you some time and experimentation. This is by no means the only way to make an HDRI, but it is a good introduction to the process.

By the end of this tutorial, you’ll have made your very own 360º HDR environment map that can be used to light a 3D scene.

Buckle your seat belts boys and girls, because this is gonna be a long one!

What is an HDRI?

Before we actually get into making anything, it’s important to thoroughly understand what it is that we’re doing, and demystify some of the confusion around the subject.

If you’re already confident that you know what an HDRI actually is, scroll down to the “Creating an HDRI” section.

In short:

An HDRI is a panoramic photograph that covers the entire field of vision and contains a large amount of data (typically 32 bits per pixel per channel) which can be used to emit light into a CG 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”.

To illustrate the difference between a JPG and an HDR file, all we need to do is play with the brightness

http://hdrmaps.com/freebies

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s