Do you spend hours working on your scene, putting in all manner of fine details, only to hit render and be wildly disappointed how, well.. ‘fake’ your scene looks?
The biggest challenge as a CG artist when creating something intended to be as close to photoreal as possibly, is always fighting against the inevitable ‘CG-ness’ of your creation.
Of course, achieving photorealism is a complex process, and there’s a reason why it can take CG artists years to reach the top of their game. Despite this, there are a number of super quick and easy things you can do to add some vital realism to your scenes
The examples below directly refer to Blender, however, they should be able to be applied in all 3D applications.
1. Motion Blur
In Blender, motion Blur is something that won’t appear in your renders by default. You actually have to click the checkbox under render properties. From here, you have control shutter speed as you would a regular camera (increase the value for more blur, decrease it for less).
It’s amazing how much motion blur adds to your animations, but it can be equally important to add to your still renders.
If you think about when you take a photo. Often, there are objects in the scene that will still suffer from motion blur. Think flying birds, swaying tree branches. It’s important not to go overboard with this but it’s something to think about in your stills. Should you want to add motion blur to objects in your scene, you’ll have to give the object some animation either side of the frame; you won’t need to spend too much time worrying about what this movement is, however, as the purpose of this is just so you can trigger that desired vector blur in the one still frame.
2. Chromatic Aberration/Lens Distortion
Realism in CG is often focused on creating imperfections that you get in real-world cameras. This can often include, but is not limited to, something called chromatic aberration, as well as the natural distortion you get at the edges of your frames due to the camera’s lens.
Firstly, what is chromatic aberration? I am no camera scientist, but in (kind of) layman's terms it is the phenomena that occurs when the camera’s lens incorrectly refracts (bends) the colours coming in; this results in a misalignment, as the colours are not being combined as they should. Essentially it’s where you get multi-coloured ghosting artifacts around objects and subjects. A lot of retro camera filters actually add this to achieve a more dated look.
Adding lens distortion to your renders will slightly distort the straight lines in your images, especially towards the edges of your frame. This emulates how a real-world acts; check out how the straight line edges of the object in frame aren’t so straight in the render below.
It is super easy to apply both of these to your renders in Blender. In the compositor, search for the Lens Distortion node and have a play around with the settings.
The Distort value distorts the edges of your frame, to create that curved lens effect. The Disperse value will split the colours towards the edges for that chromatic aberration that we’re after. With both of these, if it’s realism you’re after and not something excessively stylised, using them in moderation is key.
3. Depth of Field
This is a nice easy win.
Real camera’s have a limit to how big a range of distance they can keep in focus at any one time; this is controlled by the lens’ aperture. The more closed the lens’ aperture is, the sharper everything will be (the deeper the depth of field). The wider the aperture, the shallower the depth of field.
4. Camera Shake
Often the biggest giveaway of a CG shot is a silky smooth camera move that just doesn’t feel grounded in reality. As a first general rule if you’re after realism and don’t want your shot to draw attention to its artifice, try and ensure that your camera move is something that could feasibly be pulled off in the real world.Ask yourself, would it be a dolly shot? A crane shot? Mounted on a vehicle of some kind? And really try and emulate that kind of movement.
Secondly; in reality, even shots utilising the latest motorised camera dollies may not be perfect in stability. With this in mind, consider adding minor noise to the camera’s animation in the graph editor. Even just a little can go a long way, without triggering any nausea in your audience.
5. Grain
Real world digital cameras today have pictures that are so pristine that a lot of filmmakers are shunning it in favour of good ol’ traditional film stock if their budgets allow.
Film has that texture that is lacking in digital 4k cameras and CG renders. Adding a touch back into the scene in post goes a long way to add some extra realism to your CG shots. Not to mention, adding noise and grain back in, as backwards as it sounds, also helps tie CG with live action.
6. Exposure
Something that you should always do as default, is set the colour profile to filmic log, within the Colour Management tab. This will set the colour management to better reflect log picture profiles in real world cameras.
In real-life, lower-end camera’s with a lower dynamic range will tend to blow out extremely bright areas such as the sky. Consider this in your renders too, if you are going for photo-realism.
7. Materials
Your renders can live or die by your objects’ materials.
The addition of the Principled BSDF Shader in recent years has been a godsend, providing you with all of the inputs necessary to dial in some stunningly realistic materials. Don’t skimp on time spent really working on your roughness maps, surface imperfections, bump maps etc.
Also though, consider the areas of your scene that will need the most attention when it comes to materials. Objects in focus in the foreground should of course be priority, don’t spend hours working on the materials for way back in your scene that will be drenched in mist anyway (or your lovely volumetric fog - more on that below).
8. Bevel
You may have noticed that perfectly straight edges and corners, as found on Blender’s default cube, don’t often exist in the real world.
We can emulate this using a simple bevel modifier on the objects in your scene. It can really help even the most simple of objects feel a little more real, even if it’s just a very minor bevel depth.
9. Volumetric Lighting
I have a real soft spot for this one.
Filling your scene with volumetrics almost always guarantees a more pleasing render. Honestly, once you start, you won’t be able to stop using it.
Yes, it can add a fair bit of render time to your scenes, but the rewards are great. Using volumetrics, by adding a Cube with a principled volume shader that surrounds everything, as opposed to creating fog in the compositor with a Mist pass, results in the lighting being affected to create a more realistic result. Your light will be bounced around by the volumetrics in the cube, hence the added render time. But just look at the difference below.
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