This should just be a small introduction to realistic rendering and some tricks and tips that hopefully really can help you. If you want to learn more please jump on my vimeo channel and learn a lot of stuff for free.
Tip 1 - Don't Blame The Render Engine
Never blame a render engine if something doesn't look right. All of the most famous render engines like Arnold, Vray, Renderman, Guerilla Render, Corona, Maxwell, Octane, Redshift etc. are capable of achieving super realistic results. It‘s always the artist that makes the difference. Factors such as geometry load, usability, render times, project size, your setup (CPU/GPU),3D application that you use, etc will of course make you choose one render engine over another, but that's about it.
Once you do choose an engine, really try to learn one first and really focus on it. When I started out with V-Ray, my first engine, it was difficult to wrap my head around it, but after a while it became easier to work with, and all of the other engines that I added to my arsenal later where really a piece of cake to learn because they all work in similar ways - at least if you think about shading/material setup.
Tip 2 - Embrace Imperfections
Nothing is 100% round, nothing is 100% white or black and nothing has a perfect edge. What our eyes see everyday is imperfection, and this is exactly what we try to archive in 3D. Of course, you might have a client that says he needs a super slick product shot, but adding a dirt texture to the glossy paint and the bump with a really really low amount can make the difference between "realistic" and "wow, is that a photo?" A lot of components play together - that's for sure - but if you combine all of the little details together, you will probably get the image that you are after.
Tip 3 - Continue Learning
Watch as many tutorials as you can from knowledgeable artists. No matter if they are for your 3D application or not. Most of the time, you can translate them easily and get a huge use out of them.
Tip 4 - Take a Break From Looking at Your Image
If you have completed a project and you want to upload it to Facebook, Twitter, etc., hold back for a second and really have a look at it again. Stand up and leave your PC for 2-3 hours, then revisit it and think, does it really look good? Or do you still see something that you don‘t like? I can promise you one thing: if you can see that there is something wrong, everybody else will see it as well. Jump back in the scene and correct it even though you don't think you can hold yourself back anymore by hitting this upload button.
Tip 5 - Find A Workflow
Try to find your own workflow that works best for you. Years back, when I tried to produce my first realistic shots, I was really struggling a lot to find the problem in my shots. Is it the light? the shader? the texture? Now, when I have my model in the scene set up, I simply add an HDRi before I do any shading or texturing. I play with it for 10-20 seconds till the light looks right (not overexposed and not too dark, just the right amount). I then go from to my shader/texture procedure, changing the HDRi afterwards or maybe using area lights instead. If shading is done right, it should hold up under all conditions anyway.
Tip 6 - Keep It Simple!
I always try to create my materials as simply as I can, and if that isn't good enough, then I try to add a little bit more. Go with
a diffuse, go with a glossiness and play with the IOR, and then have a look at it in your scene with a simple HDRi setup.
Then maybe add a texture to the glossy channel and tweak it until it does look right in your live preview or whatever you are using. After that, maybe add a bump and repeat the process step by step until you are satisfied. If you tick on all channels and throw everything in right at the beginning, it might be hard to find the failure afterwards.
Tip 7 - Seek Critique
Show your work to as many good artists as you can and let them have a look at it. Never take the criticism that might come back personally. Instead, make use out of it and do better next time. Nobody was born perfect or without failures besides Chuck Norris. They learned it the same way so you should as well.
Tip 8 - Ask for Help
You might also want to try to getting in touch with one of your favorite artists to ask them for help or some tricks and tips. When I started out with this whole 3D thing, I had Raphael Rau aka SilverwingVFX by my side who helped me a lot to overcome problems and helped me with specific questions that I had. Don‘t be shy to ask for help, if they have no time for that right now they will tell you anyway.
Remember, never try to be someone else, be your own hero and work hard for it. "Success is going from failure to failure without losing enthusiasm" - Winston Churchill
CGSociety extends a big thank you to Dominik Dammelhart for his time and valuable advice!