An Unusual Approach to Photorealism With Cinema 4D & Redshift

With his animation "Light is just fine now", Marc Potocnik, Designer and Director of the animation studio renderbaron, has captured the fleetingness of everyday lighting situations to moving pixels. Marc has shared a comprehensive breakdown of how he achieved photorealism – with an unusual approach.

Light Is Just Fine Now

Light Is Just Fine Now is a free animation work I created with Cinema 4D and Redshift. It is about the fascination and fleetingness of everyday light situations. A worn-out living room in early spring flooded with light, two people talking, and street noises in the background. You can watch it on renderbarons' website.

If the scene looks familiar and you don't know why – the animation is based on a scene I created as a test scene for Maxon Cinebench.

Contemplating on light – that is also how I created the lighting for this work: photorealism is achieved only by using roughly a dozen manually placed lights, and that's (almost) it. There is no Global Illumination here. But as GI is almost free in Redshift, why on Earth would anyone do this?

For my free works, I use only manually set light and thus Direct Illumination, as this approach is kind of a passion of mine. This manual workflow lets you dive deep into the visual mechanisms of direct and indirect light the most. Combined with the efficient and elegant use of as few light sources as possible, it's an excellent lighting exercise. Yes, it sounds vintage – but hey, do you know any other artist achieving this level of realistic lighting without GI? I'll take any challenge.

Photorealism Handmade

Let's have a look behind the scenes. All assets and textures are custom-made. This, of course, also applies to shaders, be it the fuzzy fabric covering of the sofa (seen at 00:08), the worn wood veneer for the table (00:16), or the procedural marble look on the laminate of the windowsill (00:32).

However, as the name of the animation "Light Is Just Fine Now" suggests – the most important part of realism here is the light. A convincing balance of direct and indirect light is crucial to a photorealistic impression. So let's take a look at how this is achieved here step by step:

  • With textures and shaders applied, the scene is just black. Only very faint specular reflections of the background image are visible and create slightly saturated beige accents in the room.
  • As a next step, a Redhsift Sky is activated. This creates faint reflections of a blueish tone all over the room.
  • The first real lighting is then created by two Area Lights in an approximate extension of the windows. One in front and one on the right, outside the camera frustum.
  • Direct sunlight is created by using an RS Infinite Light with a slightly yellowish tint. In contrast to the RS Physical Sun, the tilt of the sun does not influence the coloring of the light, so this approach offers us greater creative freedom. To make the softness of the shadows match the hazy background image, the Shadow Softness is set to 1.
  • In nature, atmospheric haze scatters the sunlight. Therefore, I added a second RS Infinite Light with a slightly bluer hue and a much higher shadow softness of 20. Thereby this light is more or less directional daylight.
  • Let's now have a look at the making of the indirect light here. The indirect light of the sun is represented by a yellowish area light emitting from the direction of the wall. 
  • That's also the case with indirect daylight on the right side.
  • And where light bounces back and forth from colored walls, its color also gets distributed. To achieve this, a large area light in the color of the walls is placed on the left wall.
  • For indirect sunlight bouncing off the white chair, a disc-shaped area light is put above the chair. 
  • As a last step, a diffuse brightening of the room is done by a large area light in the color of the walls placed above and behind the camera.

Caustics and Not So Caustics

A photorealistic impression is not only achieved by diffuse and specular reflections: caustic artifacts from refraction and reflection are also an important part. So let's check how caustics are created here:

  • For the glass candle and the drinking glass, two separate spot light sources with small physical extensions and in the direction of the sun are placed in the scene. These light sources only create only caustics with a huge amount of photons.
  • The complex-looking caustics effect on the wall, on the other hand, is created just by a spot light with a self-painted opacity texture applied to it. 

Some Special Sauce

After lighting and caustics, there are two cheap tricks that can help with brightening up shadows that might appear too dark: 

  • On the wall, I just dialed in a minimal emission in the RGB value of the diffuse color.
  • A last slight tone mapping by the Redshift camera does the last finish in that respect.

And that's it. Especially the last two steps give our scene a slightly flat impression but are rendered with 16-bit depth – that's exactly what we want in Compositing, as this gives us enough headroom for sufficient gradation correction without causing banding.

Breathing Life Into It – With Imperfections

Well-crafted lighting, convincing assets, and textures create a realistic impression. But the movement, compositing with optical imperfections, and a corresponding sound complement this to real photorealism:

  • The photographed tree on the background plate is replaced by an animated tree with correspondingly moving shadows projected on the wall. Creation and animation of the tree are done with the 3DQuakers Forester plug-in for Cinema 4D.
  • Realism is underlined by a camera animation that simulates the behavior of a handheld camera. The camera animation is based on a simple keyframe animation, which is then spiced up with procedural movements by Cinema 4D's MotionCam. 

Compositing was done in After Effects. There I turned the slightly flat look of the raw 16-bit rendering into a photographic impression by increasing contrast and introducing optical artifacts such as Motion Blur, Glow, Chromatic Aberration, and slight animated focus shifts. Making it imperfect is making it convincing.

  • And where there are optical imperfections, auditory imperfections complement a highly realistic overall audiovisual result. The sound was recorded live with the stereo mic of my Sony Alpha 77 MK2 DSLR while I walked through a similar interior. Without further processing, the sound was added in After Effects. Yes, it's that simple.

The Hardware

The animation was created and rendered using an HP Z840 workstation with 128 GB RAM and an MSI 3090 Suprim X GPU with 24 GB VRAM. The render times per frame were about 7 minutes for the total shot and 50-60 minutes in UltraCloseUp on the candle. 

These differences come from the different proportions of expensive calculations in the image. In the total shot soft diffuse light and multiple rough reflections are already apparent, but the closer the camera gets, the greater the proportion of these and other highly complex effects gets.

This becomes especially apparent in the ultra close-up of the candle: here, widely scattered SubSurface Scattering dominates and is derived from multiply refracted and reflected light – in noise-free quality. As denoisers tend to blur the finest details, a correspondingly high number of samples is the only way to go here. But I think this was worth it.

See a making-of on the animation at renderbarons' YouTube channel:

Want to Learn Redshift?

As I am a Cinema 4D Master Trainer you can learn Redshift in my studio renderbaron – onsite and online. The scene Light Is Just Fine Now is included in the training (of course also with Global Illumination) as one of many practice projects. Check out my training courses here.

About the Author

Marc Potocnik is a graduate designer (FH) and owner of the animation studio renderbaron in Düsseldorf/ Germany. Since 2001, renderbaron is crafting high-quality 3D animations for renowned customers such as ZDF, Intel, Siemens, and others.

As Maxon Authorized Training Center (ATC) renderbaron offers trainings on Cinema 4D & Redshift. Marc Potocnik is Cinema 4D Master Trainer and also shares his knowledge by giving lectures at international industry events such as Siggraph, FMX, IBC, etc.

You can learn more about the studio by visiting its Facebook page, YouTube channel, and official website.

Marc Potocnik, Designer and Director of renderbaron

Interview conducted by Arti Burton

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