Wednesday, 9 March 2016

Useful Techniques for Underwater Lighting in C4D

Having recently finished a Subsea animation for Swagger, I came across some lighting techniques I found useful to bring an underwater scene to life. Check out the clip:

My main goal for lighting an underwater scene in 3D is to give the viewer the impression that you are underwater without having to actually have water in your scene. This can be achieved in many different ways and like most things in 3D, there is not one right way to go about it. With that being said let’s dive into how I got this look!

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I started off with an Environment Object in Cinema 4D (C4D) to bring some fog into the scene. For this project, a majority of the action was on the seafloor. At that depth the water is dark and murky, most of the light doesn’t make it this far. An Environment Object helps give this murky look with the use of fog. This project had more of an artistic approach to it rather than a photo real look so I chose some blue shades. The strength and distance were dependent on how big my total environment was so I had to tweak these values until the edges of my scene were lost in the fog. This saves some time modeling but also left the impression that the seafloor was very far down.

Notice in the image below how this shot would look without fog (left) and how it does with the fog (right). The Environment Object also helped lessen the harshness of the shadows in my scene, which I found quite useful.

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The next step in my lighting process was to add some volumetric lights to the scene. A volumetric light casts beams of light that you can see, think of sunbeams shining through the trees or light shining into a dusty room. In C4D, there is a nifty option that applies this to any light you have under the Visible Light option. Rather than set up multiple light sources casting these beams and animating each one to move slightly different to get the underwater look I took advantage of some of the Mograph tools C4D has to offer.

Using Mograph cloners I set up an array of tubes that would be influenced by a Random Effector giving them a swaying motion. As the volumetric light passes through these the light gets split up, this gives multiple shadows/beams for just one light. This technique saved me quite a bit of time!


With volumetric lighting and a nice fog environment, my next challenge was to get some caustics to show up on the seafloor. Caustics are light rays that are reflected or refracted by a curved surface. These can be easily seen in a swimming pool on a sunny day, they are the light glimmers on the bottom of the pool caused by the waves at the surface and how they bend the light. In the real world deep at the bottom of the sea, you likely wouldn’t see these as most of the light has dissipated, however, I wanted to add these to the scene to match my artistic approach. C4D has the option to add caustics to your lights but I took a different approach by creating a material and applying it to my light, causing it to act similarly to a projector!

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Utilizing the Transparency channel I animated a Cranal Noise that had its black and white values flipped. This noise would slowly move in the X and Z direction giving the impression of waves moving on the surface. This material was then applied to a blue spotlight and acted like an alpha; the light shining brightest through the areas of white in the noise and less so in the darker areas.

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In this image, you can see the difference between not having and having caustics in the scene. They add quite a bit more detail to the environment without being too complicated to set up. This shot would feel a whole lot different without their inclusion.

A final touch that I added to my scene was the addition of some negative lights. Surprisingly enough you can add lights to a scene that have a negative brightness value. What this does is add dark areas to your scene that you can easily control.

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Setting up a few of these negative lights in my scene gave me control on what areas I wanted darker with ease. I also found that they helped exaggerate some of the colors thrown out by my volumetric and caustic casting lights which was an overall perk.

In my scene, I only used three of these negative lights and you can see below the incredible difference between not having them and having them in the scene!

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What sort of useful lighting techniques have you used for projects deep in the ocean depths or above it? What lighting features do you find useful that you haven’t noticed before in your software? Feel free to share your thoughts in the comment section below or tweet @Swagger_Media! And if you’re interested in a 3D animation project, our team is here to assist you. Give us a call at 832-831-7592!

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