Interview: Understanding 3D Art Lighting Through Landscape Painting

Your paintings are focused on outdoor observation under different lighting conditions. What are the most important lessons you've learned from painting light in the real world?

Painting outside, also known as "Plein air" painting, has allowed me to gain a much better sense of color and light. Through direct observation and trying to mix the colors that I see, I start to understand what the perceived color of an object might be vs what the color actually is. Time of the day makes all the difference for how the environment looks.

Most artists normally paint in 2–3 windows of time. Normally 7 am–11 am or afternoon 1 pm–6 pm, or if you're going for an evening lighting, 4 pm- sunset. We generally try to avoid painting at exactly noon. The sun is directly overhead, so it flattens everything in your scene; there are no shadows to separate the planes in your picture.  

You have 2 main aspects that separate the objects in your scene: value, which is essentially the light or dark of objects, and atmosphere. Atmosphere is the actual effect of air and moisture on what you see. Distant mountains appear lighter and cooler because you're looking through layers of air.

During late afternoon/evening, the atmosphere becomes thicker. This is due to light traveling through more air as the sun lowers, scattering blue wavelengths and creating warmer oranges and yellows; distant objects often become softer and more unified.

When working on a painting outdoors, what are you paying the most attention to — color relationships, value structure, atmosphere, or something else?

When starting any painting, there is always a hierarchy of elements to consider.

1. Composition — shape.
2. Value — lights or darks.
3. Color — hue/temperature.
4. Edges — soft/hard edges.
5. Detail.
   

I always start with a general outline; this establishes my overall composition. Generally, a landscape will have between 3 and 5 values. This is the overall value of the main shapes in your scene that are assigned a light or dark value. This is how you establish your composition and create a separation of objects and the illusion of depth by contrasting a dark shape next to a light shape.

Once I have my outline, I will start by establishing the shadows in my scene. The light slightly changes roughly every 10 mins, so it's important to lock in your dark shapes in the scene first. Once that's done, I start adding some of my lights and the overall color of each object.

Your paintings are focused on outdoor observation under different lighting conditions. What are the most important lessons you've learned from painting light in the real world?

To start, it's just how much the colors will shift over time. In the afternoon, the sunlight is more of a white colored light. As the light shifts more towards evening, the color changes more towards a yellow, eventually to orange just before dusk. Another aspect is that shadows get longer and shift more toward a blue color because the sun is lower in the sky and there's less warm direct light reaching into the shadows.

As the sun drops, the atmosphere filters out more of the warmer wavelengths from the indirect light, so the cooler skylight has a stronger influence on the shadow color.

Another very important factor to consider is that colors that are captured by a camera will always be slightly different from what the human eye can see. Cameras are great at capturing detail but usually lack capturing the subtle shift of colors. Primarily in the shadows, cameras tend to mute colors, with the shadows looking gray, almost black. In real life, there are subtle tones in shadow from either ambient light or reflected light from nearby objects.

In the painting below, you can see there are subtle green and blue tones in the distant trees; in addition, the shadow side of the barn has a dark magenta color in it. In the photo, both of these appear as dark grey.

Another example of the difference between what the cameras capture and what the human eye sees. Below is a waterfall scene in Bassi Falls, El Dorado forest.

Even in the white of the water where the sunlight hits it, there are subtle gray tones. In the photo, these values are blown out and appear pure white. The same applies to shadows; there are subtle blues or purple tones in the rock shadows from ambient or reflected light.

Even where the rock's surface is recessed inwards, the division between the rocks appears to be a dark gray shadow; in reality, it has a warm brown tone to it. This is due to the warm reflected light bouncing off the surface where direct sunlight is hitting the rock. 

In your experience, what are the biggest differences between how light behaves in real life versus how it's typically approached in 3D engines?

I would say the game engine lighting system is obviously meant to replicate what occurs in real life. In Unreal Engine 5, you have a direct light which mimics the sun, and you have the skylight which mimics the ambient light from the sky, and you have global illumination to account for how light bounces off surfaces and illuminates other areas.

The closest we can come to how lighting behaves in real life is by using ray tracing in Unreal Engine 5, which is a rendering technique that simulates how light physically behaves in the real world. Instead of relying on approximations, the engine traces the paths of light rays as they bounce around a scene, producing more realistic lighting, shadows, reflections, and indirect illumination.

The biggest difference between how light behaves in real life vs the 3D engine is the subtlety of the colors in the scene and all the bounced light. In the 3D engine, this can be faked by plugging an HDRI (High Dynamic Range Image) into a Skylight in Unreal Engine 5. This gives the scene a much more realistic and specific lighting environment. A normal Skylight samples a simple sky color and fills shadows evenly.

Using an HDRI contains actual brightness information from a real environment, so light comes from different directions with different intensities. Still, there is a difference in how light behaves in real life vs a game engine. If you set up lighting in UE5 with a certain direction, light intensity, color, etc, each scene will have the same light setup.

In real life, there's always a difference in lighting due to subtle aspects such as geographical location, the amount of dust or moisture in the atmosphere, cloud formation, etc. Even going to the same spot in real life on a clear day during the same time of day can still look different each time.

Lighting Setup in Unreal Engine

For daytime natural lighting, I'm using a direct light: either a skylight with an HDRI plugged into a cube map or an HDRI backdrop for my skylight, exponential height fog to control the amount of atmospheric fog, and volumetric cloud. I can fake some bounced light or ambient light from a window opening using Rect lights.

For this specific project, I decided to use an Ultra dynamic sky plug-in in Unreal Engine 5. It takes a lot of the manual lighting setup and instead simulates how the sun acts in real life. When the direction of light is overhead, like it's noon, the light color is more white; when it's lower, closer to late afternoon, it's more on the yellow side. I'm using the sunlight intensity at 10 and giving it a bit of a yellow color to really push that early evening lighting.

I'm also using a single Rect light to simulate the ambient sky light coming through the window. This lights up the scene and gives the surface materials more three-dimensionality.

This is a common technique used in architectural visualization, where we use Rec lights on window openings to light up a scene and make it more presentable and appealing for a viewer.

For artists who primarily work in 3D, what do you think they're missing if they don't spend time studying or practicing traditional art?

I think they are missing observational skills and a good sense of shape, composition, color, and light. Using the 3D tools only has the challenge: your 3D has to be visually appealing and match what you are going for, whether that’s based on a concept or a photo reference.

I've done an extensive amount of plein air studies both for landscapes and architecture. This really let me understand how buildings surfaces should look like, such as different material types, surface weathering, and ageing/breakup, in addition to gaining a better sense of architectural design.

When building a scene, do you think more like a painter or like a level designer, and how do those mindsets interact?

Definitely a level designer; 3D environments for games have a lot to do with gameplay metrics and consideration for the player path. In game production, we get a very simple blockout from design that shows very big shapes, random assets used a place holders.

I'd be responsible for a specific section of the map. I'd start doing the initial art blockout of buildings by looking at the photo reference gathered or any concept images. We model in BSP within game metrics; I'll lay out where buildings should be and then start an initial Art pass on each building.

This is then followed by a second Art pass; here is where I think more artistically, like a painter bringing in multiple texture layers and mixing different types of grunge while adjusting the colors of materials to match the theme we are going for. This is also where I'll add smaller props such as electric cables or conduit wrapping around the building, plants or drapery on balconies, and different set dressing to make the building appear a bit more asymmetrical in its use. I'll also use normal edge decals so make sure there are no sharp 90-degree angles, and everything has either a bevel or looks like it's naturally worn down a bit. 

Finally, how do you see this relationship between traditional and digital art evolving in your work going forward?

I'd just say, as I've been focused on painting mostly landscapes, I would like to do some larger vista landscape scenes and do 3D projects with a lot more vegetation in them. I want to have a really strong grasp of color and understand how to create different moods while still having something that feels like it can exist in real life.

Ultimately, doing traditional studies outside is about improving your overall artistic foundation. Even going outside and seeing various objects in person and taking reference photos of a subject you're trying to create in 3D is far more beneficial than merely doing an image search without ever having been in front of it.

Biography

Mohamed is a 3D Artist with over seven years of experience in the video game and tech industries, most notably working on the Call of Duty franchise at Activision. His credits include Call of Duty: Black Ops 6, Modern Warfare III, and Modern Warfare II. He is currently a 3D Artist at Higharc, specializing in photoreal architectural visualization for home design. His digital work has been featured in multiple articles and magazine publications.

Alongside his digital career, Mohamed is a traditional oil painter who creates landscape paintings inspired by nature parks across California. His paintings have been exhibited in galleries throughout California, including YoloArts Gallery, Pence Gallery, Vacaville Art Gallery, and at the Winters Art and Wine Festival. His artwork has won multiple awards, including best plein air painting and also 1st place for the people's choice award. He holds a Master's degree in Game Development from the Academy of Art University.

Here are his ArtStation and Instagram.

Mohamed Abdel Baki, Environment/Hard Surface Artist

Interview conducted by David Jagneaux