How to get good at photorealistic rendering

By , CastleView 3D
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photorealistic rendering of kitchen remodel by CastleView3D.com

3D rendering of kitchen remodel by CastleView3D.com

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.

cover of book "Digital Lighting and Rendering" by Jeremy Birn - great resource for photorealistic rendering 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.


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11 responses to “How to get good at photorealistic rendering

  1. Very good tips. I use the analogy of the point-n-shoot camera not replacing the photographer, it just lowered the point of entry. The software is still expensive, but the hardware has gotten affordable, so people can now enter the market. Once you get in, for the most part, it is just a lot of practice to get good. I like how you don’t, or at least didn’t write about, your software bias. It isn’t the software that makes the render, it is the artist. Master your software, have a vision for each render before you start, and make it happen. Thanks for the post!

  2. Thanks for your comments, WhiteBirch! Sounds like we’re on the same page about this. Good camera analogy.

    And yes about not having a software bias — I’ve seen really excellent renders done with free rendering software. (In fact, the one I posted above — one of my own personal favorites — was done in Kerkythea.) And I suppose it’s possible to produce fairly crappy ones with 3DS MAX or one of the other high-end products. It really comes down to an eye for detail — plus the patience to tweak, tweak, tweak until you get it right. 🙂

  3. Thanks Kathy. Good tips.

    Do you notice any consistencies or inconsistencies between rendering programs? Using Chief’s Phoebe (I hear) is vastly different than using something like Artlantis or another engine….and so, there seems to always be a learning curve (sometimes a spiral)..even if it’s just terminology within the set up of the scenes from one raytracer to another….

    • Hi Chris — I think the main difference between rendering apps is the amount of things you can control. I hear that CA’s X4 version of Phoebe is now much better than the X3 version (still haven’t played with it too much myself), but I think it’s still relatively simplistic in terms of the parameters it gives you control over. When I first tried Kerkythea, I was lost; then it got to feel like second nature. Upgraded to Thea — was lost again. But now I’m really getting comfortable with it. My next step will most likely be to Artlantis or maybe Max, and that learning curve looks to be VERY steep. Every program calls things by different names, and it takes a while to figure out what to tweak to get the effect you want. I’m assuming that all these learning curves will help stave off Alzheimer’s. 😉

  4. I would stick with Chief X4 and Thea as a winning combo. I don’t think max or any others can do better.

    Sam

    • Life Should Be 3D

      Well, I’m pretty fond of that combo myself — but 3DS Max + VRay seems to be what most of the architectural visualization world thinks is standard. But since I’ve invested a lot of time into learning Chief and Thea, I probably won’t be switching any time soon.

      Thanks for stopping by, Sam — nice to see you here!

  5. Good tips, Kathy.

  6. Thanks for the tips Kathy. Your story of being self taught has motivated me once again to give the Thea software another try. It really seems so complex but your end results prove that I shouldn’t give up on it.

    Thanks!
    Dulcie

    • Life Should Be 3D

      You’re welcome, Dulcie. It’s really a process of continuous improvement. I’ve been doing this since 2007 and I still learn something new with every project.

  7. I also bought the book Digital Lighting and Rendering and found it very helpful for 3d rendering 🙂

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