Summary of Findings to Date

Before commencing with any further experimentation, today has been put aside for summarising my findings thus far.

In my initial experiment with the grey spheres I observed that an understanding of light is fundamental to achieving photorealism. Within the 3D environment, three aspects of light need to closely replicate their real-world counterparts:

  • Light needs to illuminate the surface of a 3D object in a realistic way.
  • The 3D object needs to prevent light from hitting other objects in the scene and create shadows.
  • Light needs bounce off the 3D models in the form of reflections.

High Dynamic Range Images are a useful tool for creating realistic lighting as they create a natural light source and can also be used as an environment that appears within reflections. When using HDR Images, it’s useful to first light a scene by applying textures that have a solid colour of 50% grey to the 3D models. This allows the observer to adjust the exposure of the surrounding environment, replicating the light that was present when the HDRI was captured, before creating other textures.

When creating textures for 3D models is it important to use Fresnel Reflections as this type of reflection more closely replicates how light bounces in the real world. To understand what Fresnel reflections are, imagine looking at a body of water on a Sunny day, if you looked across the surface of the water you would see a lot of reflection and little of what is beneath the surface. If, on the other hand, you looked down at the water from above, you would be able to see what was below the surface and less of the reflections. This property of light needs to be emulated in the 3D environment.

In addition to this, discounting black holes, everything in the real world has a reflection, although some have very little. With this in mind, everything in the 3D environment should have some amount of reflection.

When creating textures for 3D models that will appear within a HDRI environment, it is also helpful to use colours that match the hue and saturation of the HDR environment. Once a 3D image has been rendered, Hue and Saturation adjustments applied to the entire image help to blend the two media together.

One problem with 3D renders is that everything produced is beautifully clean and sharp, as if it had been photographed with an extremely superior lens and sensor. In order to fool the human eye into believing something was captured with a camera, some of the unwanted by-products of cheaper lenses need to be replicated. This includes chromatic aberration, noise and grain, vignetting and silvering. When shooting film or animation, other artefacts such as motion blur should also be added.

It has also been observed that in the 3D environment it is possible to create perfectly square edges which, if magnified an infinite number of times, would remain perfectly square. In the real world this is less often the case as edges tend to be worn and/or rounded. To make 3D objects appear real, hard/square edges should be avoided.

It’s possible, although I haven’t as yet been able to prove or disprove this theory, that scale plays an important role in creating the illusion. We know that if we see a 60 foot gorilla on the screen, it is most likely computer generated rather than a real photograph. Similarly, in this animation of a spider, the illusion of realism is ruined because we know that spiders are not this big.

Spider Animation

Finally, it appears that it is easier to fool the human brain into believing something is real if the brain has fewer points of reference. Take for example a human hand, creating a 3D hand that an audience believes is real is extremely difficult as it is something we spend a great deal of time looking at and accordingly we have extensive points of reference. If, on the other hand, I was to create 3D model and said it was a newly discovered creature that was found deep in the ocean, it would be easier to fool the mind into believing it was real as the brain has fewer points of reference.

In account of all this, what’s next?

Although I’d very much like to continue developing the antagonist, as can be seen in the project plan, module deadlines dictate that I begin researching the findings of other practitioners and comparing their results to my own.

Before this is done, I will first address my objectives for satisfying the learning outcomes to ensure that they are all being achieved.

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One thought on “Summary of Findings to Date

  1. Pingback: Lessons on Photorealism from 3D Artist Magazine | Photorealism in 3D CGI Imagery

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