Category Archives: Lighting

How to Create Your Own HDR Environment Maps

Update: I’ve written a new HDRI tutorial that covers some more advanced stuff here:
http://blog.hdrihaven.com/how-to-create-high-quality-hdri/
It’s aimed a bit more to professional HDRI creators and assumes you already know the basics, so if you’re completely new to HDRIs you should read this post first :)

garage

A simple 3D scene that was lit using only the HDRI above (no additional lamps)

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.

Creating 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!

Continue Reading…

What Makes a Good HDRI and How to Use It Correctly

HDRIs are everywhere these days. If you’ve got a half-decent camera, a tripod and some software you can even make them yourself.

But just like creating art in Blender, being able to do it at all is not the same as being able to do it well.

So, after I created my first crappy HDRI and discovered how challenging it could be, I decided to embark on a quest. I wanted to create the perfect high dynamic range environment map that would give you perfectly accurate and realistic lighting as if you had teleported your CG scene to the actual location of the photo itself.

In truth, this is an unending quest, but I’ve made some fair progress over the years. So without further ado, let me explain…

What Makes a Good HDRI

Just like art, the quality of an HDRI can be a subjective thing, but I think we can all agree that there are a few fundamental attributes that define (although not exclusively) how useful or accurate an HDRI is.

Dynamic Range

evs_grid2

Let’s begin with what is, to me, the most important aspect of any HDR image that you intend to use for lighting.

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World Volume Tests

Most of you have probably downloaded the 2.70 RC by now and probably started playing around with volumetrics in cycles. Immediately you probably noticed how slow it renders, although that was probably expected. Here are the results of a little test I did to find out exactly how to speed up volume rendering for the world up so that it’s actually usable.

The very first and foremost thing you need to know about volumetrics is the difference between Homogeneous and Heterogeneous volumes. Basically, a volume where the density is driven by some texture is a heterogeneous one, and a volume with consistent density is a homogeneous one. The difference in render time and quality is… well, quite drastic:

Homogeneous vs Heterogeneous

Homogeneous (2m 40s, 512 samples) vs Heterogeneous (1h 4m 55s, 128 samples)

Yep, you read that right. Under 3 minutes for homogeneous volume and over an hour for a quarter of the samples in the heterogeneous volume. The heterogeneous render seems to have a less dense volume, and I guess it does since it was driven by a noise texture where I couldn’t easily control the density and honestly couldn’t be bothered to wait long enough to give it a decent try. Continue Reading…

How to Create Your Own HDR Environment Images

Download Free HDRI - lapaDownload Free HDRI - lapa

Download Free HDRI (2048×1024 - 6.6 MB)
Licensed CC0

Want more free HDRIs? Check out my new dedicated website: HDRI Haven

I searched long and hard for a way to create these magical images that light your scenes for you, and I never once found any article or mention of the process in any of the Blender forums. Every time I saw a render using image based lighting (IBL), the artist had always found it on some website (and was usually accompanied by a complaint about how Blender doesn’t give you nice hard shadows).

I’m no expert in this matter, but due to the lack of information that can be found easily, I’d like to share the little that I do know with you.

So in this guide I’ll show you the basics, but it’s up to you and the rest of the community to find out by experience what is good or bad practice and when to ignore everything you’ve ever been taught.

Continue Reading…

Killing Caustics Cleverly

Alliteration aside, this blew my mind.

joined2

The two images above were both rendered in nearly 18 minutes on a 12 core i7 CPU. All materials and settings everywhere were exactly the same… sort of.

I’ve been playing with image stacking lately, mainly as a tool to render images and animations progressively, but when rendering some glass the other day, I realized that the only reason it renders so slow is because the noise and fireflies don’t change all that much, only more and more of it gets added and eventually averaged out. So if we change the noise pattern and render less samples a couple of times…

Continue Reading…

Commonly Ignored Features #2: Contrasty HDR Lighting

Update 2016: This method is pretty much just wrong. See this post instead.

At the time Cycles came out in Alpha, I was playing around with HDR lighting in Blender internal. I found BI to be annoyingly slow and impossible to get that magic one-click lighting that all the non-blender websites had promised HDR could do.

You might remember some fool using this in some tutorial...

You might remember some fool using this in some tutorial…

So when Cycles showed up, I figured the day was saved and all my problems would magically disappear.

Well most of them did, but HDR lighting still looked flat and boring, lacking the shadows from the sun even in simplest of outdoor images.

hdr_bad

However, a couple years (has it really been that long?) later and I can now tell you where that magick one-click-lighting button is!

hdr_good

Well its not technically a button… but a single node connection:

hdr_nodes

All you need to do is connect the image to the Strength input of the Background shader and it’ll use those awesome bright pixels of the sun as the strength, meaning the sun is actually brighter than all the other white things! Hence the awesome shadows and realistic lighting.

The Multiply node is there to control the strength of the light, I increased it to 2.0 since it was a little dark, but it could probably even go higher since the shadows are a bit dark here.

Update:

Don’t forget that we’re working with nodes here people! Anything’s possible!

hdr_joined

On the left is the plain setup with the HDR plugged just into the colour.
The middle is with the node setup above, the image plugged into the strength too (brightened with a multiple math node)
And the right one is with some extra adjustments:

hdr_nodes

Notice that the colour hasn’t been altered at all.
The Multiple math node is just to brighten it up, but the orange mix node mixes that strength value with white, effectively decreasing it’s contrast and making the shadows less harsh (thanks to Sir Reyn for the great idea!)

Now the blue mix node is where it gets a little more technical: The Light Path node gives us access to the different sorts of light rays. It’s common to see people use the Is Camera Ray to make something look a certain way to the camera, but behave differently for the rest of the scene – for example making a glass object look like glass to the camera, but the rest of the scene perceives it as plain old transparency, thus eliminating caustics.
Here we’re adding the Is Camera and Is Glossy rays (making sure to Clamp them so as to keep the result between 0 and 1 and continue energy conservation) and using that as the Fac of a mix between the strength driven by the image and a consistent strength (in this case of 5.0 since that’s what is bright enough for this HDR). So to the camera and in reflections (the glossy ray), the environment looks exactly as it did before we started messing with the strength, but it still lights the scene nicely.

Hope that isn’t too confusing for ya :)

Also remember to enable Multiple Importance Sample and choose Non-Color Data for the environment texture.

 

PS: For those of you who have been hiding in a cave the last few years, Reyn’s blog is a great one to follow! A true artist he is :)