How to use Chromatic Aberration in Lumion to ensure your renders are crystal clear!
If you’ve been using Lumion for a while now, you’ll have no doubt noticed the little setting in the effects menu known as Chromatic Aberration. The first time I tried out Lumion was whilst testing out Lumion 6. At that time, the chromatic aberration was an optional setting that remained largely unused by many of the Lumion artists I was seeing. When it was used, I often found that it didn’t improve the image, instead it added an ugly distortion to the scene that made it far less appealing.
Fast forward to Lumion 8 and the creative devs over at Act 3D decided to incorporate the feature known as styles which revolutionized the way that artists used Lumion. The pre-set styles demonstrate beautiful lighting, compelling shadows, vibrant colours and an all-round better-looking image compared to what was attainable by the average user in versions prior. One thing I couldn’t help notice as Lumion 8 images began to spread across the internet however, was the obvious loss of clarity and crispness on many of the images.
After getting my hands on Lumion 8, I very quickly realized what was happening. See, the Chromatic Aberration effect was no longer buried in the effects menu. Instead, it was applied to every single style in Lumion 8. As the obsession with styles grew so did the number of images with this Chromatic Aberration applied, resulting in a flood of blurry images from those of us who misunderstood the role of Chromatic Aberration plays in an image. So let's take a deeper look and find out just what Chromatic Aberration is.
What is Chromatic Aberration?
Now I’m not going to explore the technical intricacies of chromatic aberration here. I’m far from an expert on the characteristics of camera lenses, and it’s not entirely relevant to the purpose of this article. To summarise in a way that applies best to us, chromatic aberration is essentially the result of colours appearing where they shouldn't. As the colours pass through a lens, they fail to intersect at a central focal plane and when the colour wavelengths arrive before or after this focal plane the colours are separated, resulting in chromatic aberration.
In practice, it’s a major issue that photographers have to battle with in their work, as the defect is caused by the camera itself rather than the photographer. Often, photographers go to great lengths to remove this colour fringing from their images and camera manufacturers invest millions of dollars into developing innovative ways to fix the problem.
We strive for photo-realism no matter how ugly it may be.
Chromatic Aberration in CGI
So, if this is such a major problem in photography, why on earth would we implement it into our architectural renders? Especially when we don’t even have this problem to begin with!
Well... the simple answer is that we strive for photo-realism no matter how ugly it may be. In order to achieve the level of photo-realism that we find in the real world of architectural photography, artifacts and issues such as Chromatic Aberration are composited into the image to help enforce that idea of realism. Like all powerful stylistic effects however, subtlety is key.
Chromatic Aberration in Lumion
It's here that the problem with Chromatic Aberration in Lumion lies. Although the styles that were released in Lumion 8 were a fantastic addition in providing a basis for our renders, they quickly became overused by many emerging artists.
You see, the styles that were included in the Lumion 8 release are best suited as a guide, providing a foundation for each image that could then be built upon to suit a particular scene. Instead, it was seen as a ‘one-click-render’ button which resulted in many users producing images with little to no alterations to the effects included in the styles. Now there’s no doubting that the results of the styles are often fantastic, but it’s important to remember that no specific render setting is applicable to every scene and this is especially true for the chromatic aberration setting.
The chromatic aberration that is emulated in Lumion closely resembles what is known as Transverse Chromatic Aberration, or TCA. This is often caused along high contrast edges whereby a dark area overlaps a bright area. This form of aberration causes the small red and green colour fringes that blur towards the edges of the frame and closely resemble the look within Lumion when the Chromatic Aberration effect is added.
With this in mind, it should be noted that the extent of this effect is SIGNIFICANTLY less in real life than what they are presented as in the average Lumion style. Sure, they’re present in photography, but often only at close inspection of the edges in question.
Lumion natively exaggerates these effects in the styles and this is what causes the blurred edges we see on so many images.
So When Should it be Used?
Well, as a general rule I recommend saving Chromatic Aberration for exterior shots only. Interiors are often evenly lit and therefore the presence of this type of aberration would theoretically be far less likely (especially at the level that is a standard in Lumion). Try it out on your next interior render and watch how the clarity improves in your scene. If you do feel the need to add this effect as a creative decision, another way to add this is via the Depth of Field effect. This effect has a Bokeh option along the bottom of the effect tab that mimics aberrated colors along edges that are being affected by the depth of field blur. It’s much softer and is targeted to the areas that are intentionally unfocused meaning that most of your image is left more or less clear.
For exteriors, the options are a little broader and we can get away with adding a little more in. In my experience, keeping the CA to an absolute minimum yields the best result. Push the slider to 0 and work your way up until you notice the slightest blur of your high contrast edges. Stopping here ensures that the Chromatic aberration remains closer to that of real-life photography and will help prevent any nasty blurring from occurring on your edges.
Blurry, No More!
And there you have it! A quick and easy way to ensure your renders stay clear. Chromatic Aberration is a powerful tool in adding realism to your images but it's important not to overdo it. Like many things in Arch-Viz, It's best to start with zero and work your way up to ensure nothing is needlessly added.
Did this help clear up your images? Head over to The Lumion Collective Facebook group and join the discussion. I'd love to see some of the images you create using the (very subtle) Chromatic Aberration effect, so tag #thelumioncollective on your Instagram so I can check them out!
Thanks, and I'll see you in the next post!
UPDATE: As of Lumion 10, the Chromatic Aberration effect was removed from all styles. That being said, many of the points made in this article are still relevant so I thought I'd keep this up. Thanks!