In the default settings, I would first go to the clamping settings and set the indirect clamping to 50, rather than the default of 10.
I would not disable the filter glossy, unless you are specifically trying to render caustics. If you have a glass object casting a highlight through its shadow, you can reduce filter glossy to make that highlight sharper, but you would have to test how low you can get away with before the scene turns into a mess of fireflies.
The light paths (the number of bounces) are set a bit low if you want maximum realism. The defaults are good for animation, where render performance matters. But for a still image, you can get away with more. This is especially important for volumes, which default at 0 bounces. If you were to render volumetric clouds, they would look too dark without a few bounces.
I have especially increased glossy and transmission, because you can actually need to use that many bounces, for scenes with lots of glass objects or water simulations.
The default color management settings can look a bit flat. I like to set the look to medium high contrast. Though this depends on what you do in the compositor, as you can also fix the problem there.
The “film” section of the render settings has a filter width setting which might interest you. This controls how blurry the render is. The default is 1.5, which means each pixel will be blurred half way across it’s neighbors. This is not unrealistic, as real photos are a bit blurry. A value of 1 means no blurring at all, each pixel keeps to itself exactly. A value under 1 means the anti-aliasing will get reduced, giving you a sharpened look. As you approach 0, you will get something that looks pixellated.
I have no recommendation in particular for this settings, as it depends on the look you are going for and the resolution of the image, but it’s good to know about it.
Now, let’s talk about the sampling settings. They don’t affect realism, but are relevant for render speed and quality. I like to change them to something like this, which I believe to be better fitted to the average scene than the default values:
Quick explanation of what each setting does:
-
Noise treshold: used to speed up the render. It does this by looking at each pixel and trying to figure out if it’s below a certain amount of noise. If the pixel is clean enough, it gets deactivated, so Cycles doesn’t waste time rendering pixels that are already clean. A smaller treshold = less noise tolerated = more quality / slower render.
-
Max samples: the point at which the render will get stopped no matter what. You could also choose to disable it (set it to 100000), in which case the render will be stopped by the noise treshold instead, when every pixel has been finished (takes longer, but ensures an even amount of noise everywhere).
-
Min samples: how many samples are rendered before the noise treshold starts being used. This is important, because Cycles needs to observe the render for a while to judge the noise accurately. If you don’t have enough min samples, complicated light scenarios could be misdjudged and get stopped too soon, leaving artifacts in the noise. If you don’t pick a min samples value (leave at 0), Cycles will pick one for you based on your other settings, which may or may not be enough depending on the scene.
If your scene has glass, the usual way to deal with it is to deactivate the shadows on those materials. The more realistic way is to switch to CPU rendering and use path guiding. However, that is really slow, so I would do that only for stills.
If you are rendering volumetric clouds or smoke simulations, you can go to the volume settings and reduce the “max steps”. This will greatly speed up the rendering of complex volumes with basically no visual difference. The default of 1024 is really high, I can get away with 256 for smoke sims easily.
When making a material, you want to make sure to keep it realistic.
Unless you know what you are doing, you are generally better sticking to the principled BSDF for most objects. Be wary of the add shader. If you start combining materials using it and you don’t know what you are doing, you will create materials that reflect more light than they receive and that’s not realistic.
Beware using a brightness value of 1 for the color of a diffuse surface, that never happens in real life (the default of 0.8 is about as bright as you would find in real life).
Be aware of the limitations of Bump. When you use a bump node, the “distance” setting is very important for realism. Bump is a flat effect that gives the illusion of depth without actually moving the surface. The “distance” represents how deep the effect is in meters, or rather how deep it would be if it was real.
This means that with the default settings, your bump will be shaded as if it was 1 meter deep. If you were to use true displacement with the same settings, an object that’s roughly at human scale would have huge spikes.
This means that:
- bump is best used for fine detail,
- unless you are making a bump map for a landscape or something, your distance values would likely be more in the 0.001 - 0.01 range.
Finally, keep in mind the difference between Cycles and other renderers is almost negligible compared with your own knowledge of modeling, texture, photography and lighting. If you can’t get to 99% realism in Cycles, it’s not an other renderer that will save you.
you m ight try 0 in viewport for infinite computation ?? (or it stops 16777216 ???)
