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One of the biggest misconceptions in 3D rendering is to think that the final outcome comes from "magic" and secretive rendering settings. So many people have send me notes asking me for what rendering settings I use to get the looks I show in my gallery, which sounds odd and misguided. As a matter of fact, rendering settings depend on what's in the scene, so there is no "magic" single setup that would work for all of them. Rendering looks depend on other things, so lets talk about what rendering is all about.
In a nutshell, a 3D render is a simulation of how light rays interact with different surfaces and materials. Every pixel in the final render is the result of that. Both Poser Firefly and DS 3Delight use basically the same renderer based on the open source Pixar Renderman, so the following applies to both.
There are basically two ways of rendering a scene: accounting for all physically correct interactions of light rays with surfaces and materials, or instead try to simplify those for the sake of faster and easier to set up renders. Physically correct rendering is called "unbiased", while simplified and approximated models of it are called "biased" rendering. The prior takes longer but delivers the most realistic results, while the latter renders much faster but at the cost of lower realism. Both Firefly and 3Delight lights and rendering are of the biased kind. Note that I've mentioned that not only the renderers are biased, but the lights and materials are too, meaning they are also not physically correct.
One may ask why not always render with unbiased renderers, and as a matter of fact, some of the early rendering engines tried to go that way, but in theory, an unbiased render will "never end". That's because when real light hits an object, part of it is absorved, part is reflected and go hitting other objects and repeat the process until all energy is spent. Computers can only work with "discrete" numbers, meaning it cannot calculate things to infinity. In practical terms, this means a computer may never finish calculating all possible light interactions that happen in the real physical world. If it did, we would always get the ultimate level of realism in every render - but only if we could wait forever for it to finish.
Modern rendering engines use a mix of biased and unbiased rendering solutions that try to get the best of both sides in a controllable (and reasonable) amount of time. There are ways to "fake" real infinite light interactions in a more concise way and still get a reasonable result in a fraction of the time. Computer science keeps coming out with new solutions every now and then, but at least one thing is still necessary to obtain realism - ray tracing. This is still the Holy Grail of 3D rendering, and also one of the most used features.
Ray tracing is the process of simulating light rays being emitted from a light source, bouncing off whatever it hits, get refracted and/or reflected depending on the material it hits, and then eventually "die" after a certain number of interactions. Only light rays that can be seen from the camera are accounted for. Both Firefly and 3Delight use ray tracing, where we can manually set the number of times a ray can bounce before it dies, and also the number of light rays to cast. This alone can dramatically affect rendering quality when it comes to what makes images look real, such as shadows, reflections and refractions.
You will notice, though, that the default number of bounces is set to a very low value (usually "1") in both rendering engines. The reason is simple: the more bounces, the longer a render will take to complete. A value of "1" can get you precise shadows, but unrealistic reflections, and no refractions. But since these renderers are both biased, even crazy amounts of ray tracing would still not calculate how light interacts with translucid objects such as glass, which should produce refracted lights coming out of them and hitting other objects (this is called "caustics"). Neither Firefly nor 3Delight support that.
From this we can see that biased rendering engines have limitations - even when using almighty ray tracing, there are still things they cannot do. There are ways to simulate some of those things, like for example, how one object can cast very subtle shadows over it's close proximity that really happen in the real world, but are usually not accounted for in biased renders. A mathematical algorithm called AO ("ambient occlusion") does just that much faster than it would take to do the same with more advanced methods.
Another physical phenomenon that can be faked in 3D is the way an object can reflect light emitted from another object, and illuminate other surrounding objects with it. For example, the moon reflects the light from the sun and illuminates the Earth during the night, even when the moon itself does not produce any lights. This is called IDL ("indirect lighting"), and while most biased renderers will not account for this, it can be approximated in a fraction of the time it would take to reproduce it with full ray tracing (by using fewer rays and guessing the rest by means of interpolation). Poser's Firefly renderer supports AO and IDL natively, but remember these are meant to fake reality.
Exactly because biased renderers will always fake reality, and in some cases even lack the ability to do that, I have quit using Firefly last year, and adopted Octane as my default renderer in Poser. Some of you may have noticed some visible differences in the images I have been posting since then, since Octane is an unbiased renderer.
If you have been following my train of thought, we can conclude that Octane cannot use any lights, materials or cameras from Poser because they are all "fake". There is a lot of myth going around about how this or that program can do a better material "conversion" from Poser to Octane, but the truth is that this is better done manually because biased and unbiased materials are based on completely different laws. If they manage to get you a good conversion, it was most likely a matter of luck and guessing.
Although modern rendering engines try to simplify things the best they can, chances are that it will be difficult to produce realistic looking renders if you don't understand what the tools do. For instance, knowing what ray tracing, AO and IDL do can help deciding when to use them and in what amount. Hence always using all features to the maximum settings will only guarantee the render will always take the longest time to complete.
With unbiased renderers like Octane, Lux and others, things work quite differently. While things are rather complex to setup in biased renderers, unbiased engines are much easier to configure, in part because there aren't such multiple options for things to fake. Having that said, Octane is not a single rendering engine, but several in one. This "hybrid" approach has become common with unbiased renderers as means to reduce rendering times.
Unbiased renderers will try to simulate the way real lights work in the real world, but as we have seen above, this can easily lead to endless rendering times. There are several theoretical models to simulate real light, and each has pros and cons, but the main objective is to produce the best results in the shortest time. Here again, it is important to understand what each is trying to accomplish, because just setting everything to max values will only make them take longer - not necessarily better.
Biased renders have multiple kinds of lights, such as point, distant, and spotlights. Unbiased lights only exist in two kinds: Sunlight and area lights. At first, one may think this is too limited, since my main kind of light used to be the spotlight, and those don't exist in Octane. In reality, Sunlight is similar to a distant light, except that there can be only one in the scene, and it directly affects it's own "physical sky". Sunlight is most useful for architectural visualization, so I don't use it so much.
The real gold is on the area lights, which can be used to replace any other kinds of biased lights, and with advantages. For starters, area lights can have any shape and size, so if you want to make a point light, just make an area light out of a sphere. Want to make a spotlight or distant light? Create an area light out of a plane - it's that easy. A simple plane area light can easily simulate a photographer's softbox, which would require much more work with biased lights.
Now back to unbiased renderers, typical rendering cores are Direct Light, PMC, and Path Tracing. Direct Light is the only biased option, and not surprisingly, it can be very fast at the cost of not supporting some more advanced features. If your scene uses Sunlight and has no (or few) semi-transparent objects, it will produce decent results using Direct Light with fake ray tracing, IDL and AO - in most cases much better than what you can get with Firefly or 3Delight.
PMC is the traditional "Monte Carlo" brute force ray tracing method. It's an optimized version that can produce the best caustics and refraction results - but only if your scene has objects that require that. Otherwise it will just take longer than necessary to complete the render. PMC is by nature slower than the other cores, but when it comes to scene with refractions and caustics, it will do it faster than the others.
Path Finding is by far the rendering core I use the most, and to no surprise it is also the default core in Octane. This core produces the best trade off between quality and rendering times, but it may lag behind PMC if your scene has lots of transparency, refractions, and caustics.
This is a classic example of how important it is to know what each rendering core is good for, so we can pick the right one for the job in hands. By now you should know when to use each of them, and why it depends on what's in the scene. With biased renderers from Poser and DS it is still the same thing - we can get much better results when we know what the features do, so we can choose when to use them to our advantage. For instance, increasing number of ray tracing bounces in Poser or DS will be a complete waste of time if the scene doesn't have complex reflections and/or refractions over semi-transparent objects, for this alone can easily explode rendering times with no visible gains.
I hope this will help people understand that it's a myth to believe there is some secret rendering setting that makes all renders look good. In a nutshell: what comes out of a render is the result of how well the materials and lights react to each other, based on the kind of rendering engine that is doing he job. Learn what your particular rendering engine is trying to do (or fake), and make educated decisions of where and when, and in what amount to use them.
Have fun and render!