7 Lessons on Photorealism we can learn from Alex Roman

We will talk about:

  • Some essential tips from Alex Roman's latest book 'From Bits to Lens'

Photorealism. The holy grail of CG. Why can some artists pull it off, but others don't get close?

Well in large part it comes down to these 7 Fundamental Lessons.

These lessons are largely based on the From Bits to Lens, by Alex Roman - which unfortunately you can no longer buy :(

I wanted to do an episode on this book because it's packed with good information. In the book Alex Roman gives great advice on achieving photorealism, which I've condensed and summarized into the 7 points below.

1. Attention to Detail is Key

“Observation is crucial to graphic artists. At first glance, you might struggle to put your finger on why an image looks synthetic (CG imagery) and not like an actual photograph… The answer might not come immediately, it boils down to the fact that you can’t trick your brain. Brains can quickly tell the difference... 

There are thousands of physical details that come together to produce the final CG image... Many a time, when rendering a relatively simple structure, we end up with a result that is barely realistic or quite unrealistic because we often forget to add all the invisible details from the real world...” -Alex Roman, From Bits to Lens

This will improve with time but you can accelerate the learning process by trying to reproduce a photograph in CG. Doing so will force your eyes to pick out the tiny amounts of details that were previously invisible.

2. Study Lighting and Materials

“...90% of the time, the materials and lighting carry the weight of creating truly photorealistic imagery.” -Alex Roman, From Bits to Lens

Modeling can be one of the more fun tasks, as we can see the results in realtime.

But in terms of photorealism, materials and the lighting can often play the biggest role.

Knowing how to make a wooden floor reflect sunlight realistically requires more than just slapping on a texture and hitting render. It requires understanding the intricate details in the bump mapping, the reflectivity, the quality of the wood, its age and as well as the time of the day, shadow softness and sky bleed. Study lighting and materials.

3. Everything is dirty

“Erosion is caused by time and the interaction of external elements, and it appears on almost all the surfaces of the objects in the real world… [of which] the most visible parts, often seem to be the most eroded." -Alex Roman, From Bits to Lens

Unless you’re making a material that’s inside an air vacuum, it’s going to be affected by the environment.

Consider the footprints that people would leave on the tiled floor, or the effect that the rain would have on an exterior wall. No matter how minimal you think the erosion will be, add it anyway. Without it your scene will always have a distinct CG feel to it.

Rule of thumb:

  • Interior? Add an accumulation of dirt around the edges.
  • External? Add physical wear and tear on the edges or erosion of the material.

4. Use HDR Images for Lighting

One of the bonuses included in The Architecture Academy – 30 HDR Skydomes

One of the bonuses included in The Architecture Academy – 30 HDR Skydomes

“Image Based Lighting techniques is the most realistic way to light a CG scene. Since this image format contains a huge amount of information on tones, color and intensity, it can be used to reproduce sunlight with a single texture, saving us from having to reproduce it using other techniques.” -Alex Roman, From Bits to Lens

HDR lighting is the king of photorealism. The reason being that the real sky contains millions of color variations and light alterations. So trying to replicate it using a simple sun lamp and colored world light is missing out on a lot.

Using an HDR light takes out the hard work. It’s the closest thing to a magic bullet. Adding it to the scene creates accurate lighting, shadows and reflections in almost one click.

The Pro-Lighting: Skies addon takes this one step further by making it available in a couple of clicks.

5. Incorporate Chaos

Randomness of the objects in our scene plays a big role in how our brains will perceive it.

“Reality is extremely complex. It is important to closely observe the model that surrounds us, which we call reality; a model that is full of imperfections, a model created by chaos... 

In real life you’d have a hard time finding a bookshelf whose books were perfectly aligned (or even the same size!), and the same applies to stretches of glass on a building’s facade or the slates of wood that compose a platform...

However small the variations in space, however slight the rotations or however imperceptible the changes in size in the continuity of similar objects, all these elements really do affect the end result of the image.” -Alex Roman, From Bits to Lens

Most artists know that a perfectly aligned fence row doesn’t exist in the real world, but adjusting each wood panel individually can sounds painful. So often out of laziness we skip it, thinking it’s unimportant. But our eye expects to see these slight imperfections. Without it, something looks wrong.

6. Know your Render Engine

"Knowing each parameter inside out, knowing what they are there for how and to enable or disable this or that check box in the renderer is crucial to making the engine genuinely work like an extension of your hand or eye, to it becoming an integral part of the artist, instead of feeling overwhelmed, cutting corners and merely shooting blindly and hoping to hit the bull's eye." -Alex Roman, From Bits to Lens

This is what can often give your render that "magic" quality that just seems photorealistic. You may be able to fake it once, but consistently hitting your mark every time takes a solid understanding into the details of the render engine.

7. Understand Cameras

Whilst photography may seem like a different subject to CGI, it goes hand in hand in terms of achieving that last 1% of photorealism.

Aperture, Shutter Speed and ISO all effect each other. Glare, chromatic abberration, barrel distortion and vignettes are caused by camera limitations. Do you know when they’re supposed to be used?

Interested in learning more? Join over 1,000 students currently learning photorealism in The Architecture Academy.

Andrew Price