Five tips for improving your photorealistic rendering skills
Over the years I’ve learned a thing or two about how to produce high-quality photorealistic renderings, and I thought some tips might be useful for anyone trying to learn or to improve their skills. But a few caveats are in order:
- I don’t consider myself an expert in this area, just someone with some knowledge to share.
- I’m completely self-trained. (If this field of study had existed when I was in school, my life might have unfolded quite differently. Or maybe not.)
- What I’m going to say may only apply to architectural rendering, because that’s all I do.
1. Train your eye.
Carefully observe the world around you to develop an understanding of the interplay of light and materials. Notice how different types of light sources interact with different material surfaces. Make mental notes about the shapes and depth of shadows and reflections. Learn some of the basic physics of photons and properties of different materials to further inform your observations of light scattering and reflection. Learn some stuff about photography to understand the ways various lenses and apertures and film types and speeds affect how a scene is captured. Learn how basic rendering terms (specular, translucent, refraction, bump, anisotropy, sub-surface scattering) relate to the things you’re observing in the real world.
You don’t have to be an artist, just a good observer.
This first step can take a long time (possibly a lifetime), but you’ll never get photorealism if you don’t get this. You have to have a deep understanding of what you’re aiming for in order to be able to guide your rendering program to produce it. Some people seem to come by this ability naturally; but it’s a skill that can be learned with discipline and motivation.
2. Master your modeling software.
No matter how good you get at rendering, or how powerful or expensive your modeling software is, you will never master photorealistic rendering if you don’t first master whatever program you use to produce your models. If the model isn’t perfect, you will never produce a rendering that is indistinguishable from a photograph (or comes really, really close), because there will always be some jarring detail that is just WRONG. It might not jump out at you, but subliminally the viewer’s eye will register that something is off. A symbol that’s too blocky, a book “floating” a half-inch above a tabletop, or a chair leg that disappears into the baseboard are all things that can subtly ruin the realism of a model. (Want to know how I know this?)
This requires more than a slight degree of obsessive-compulsiveness. Go over your model with the proverbial fine-tooth comb to identify anything that’s not quite right. Then do a preliminary render at a really big size to help you see modeling mistakes that might not have been apparent at a lower resolution. Zoom in really close and go over every detail. Only when you’re satisfied that the model is absolutely perfect should you proceed to step 3. And even then you will most likely still find things that you didn’t catch before.
3. Master your rendering software.
I can’t really give software-specific advice. At any rate, a skilled renderer who has accomplished #1 and #2 above can produce decent results with pretty much any rendering application. But whatever you use, the better you understand all the technical bells and whistles in your rendering software, the more power you will have to tweak even the smallest details to obtain the effects you want. Read the manual, do the tutorials, frequent the user forum, set up experimental renders to test lighting, materials, displacement, and special effects.
One of the best resources I know for learning more about how to set up realistic scenes for rendering (without being too software-specific) is Digital Lighting and Rendering (2nd Edition) by Jeremy Birn. A classic.
4. Practice, practice, practice.
I know this sounds like the old joke about how to get to Carnegie Hall, but there’s simply no better way to improve your skills and knowledge than to keep practicing them over and over. Set up a render; see how it looks; decide what you don’t like or what could be better; tweak your settings; render it again. Compare it to the first version (or the first 100 versions) and see whether it’s better, or not, and figure out why, or why not. Lather, rinse, repeat.
Try something new, experiment, take a risk, see what you end up with. Sometimes it won’t be pretty (the first time I tried displacement on a stone wall, it looked like the wall had blown up!). The good thing is, it’s only pixels, so no one gets hurt, even if it doesn’t work.
A lot of times I hear frustration from beginners because the software won’t “give” them the results they want — like they expect to be able to simply push a button and produce a realistic render, just like taking a photo. But your software isn’t that smart, no matter how much you paid for it. Some rendering software has very sophisticated algorithms built in with amazing plug-ins to take it even further. But the bottom line is that it can only do what you tell it to do. And this is where your trained eye and in-depth understanding of your modeling and rendering software really make all the difference. Which brings us to #5……….
5. Repeat steps 1-4 on infinite loop.
There is always more to learn, more observations to make, more to refine. Never stop trying to improve. If it starts to seem easy, you’re no longer growing or improving. Get out of your comfort zone by doing more observing, more learning, more experimenting.
These suggestions are just one person’s opinion, and may even be painfully obvious — like “duh.” So I’d love to hear others’ ideas about what you think it takes to get really good at this challenging and fascinating skill.