This thread will produce some nice images, but it will not get to the root of the issue. The real question is: “what are the benefits of unbiased rendering?”
To get anywhere, you need to specify a few things. First of all, forget about humans, they aren’t going to look realistic in any software unless you know as much about human facial expressions as you do shaders and lights. Humans are too distracting.
What you need to do is to look at specific technical things unbiased render engines can do well and see if you can recreate that in Bryce, Carrara, or Daz Studio.
Technical issues like prismatic banding of diamonds is a good test to demonstrate the benefits of unbiased rendering and why it is often so much superior to biased rendering. Again, forget humans, lets see how many Carrara users can render diamonds as well as Luxrender.
Diamonds, show me your diamonds if you dare!!!!!!!!
In order to get anywhere you need to have a good grasp of what “bias” is in the first place and why Carrara, Bryce and Daz studio are biased engines. Bias is introduced by shortcuts. Not all shortcuts are obvious to the layman viewer, but they are still there. Carrara is very good at hiding most of its biases, but they are still there. some scenarios demonstrate biases more than others, so a standardized scene is the way to go.
It is dangerous in my view to try to determine biased or unbiased status based on the final look of an image. Final results have nothing to do with it. It has to do with the way the work was approached mathematically, period. Results are meaningless.
Now I am a firm believer that the user is the final piece of the puzzle, but that isnt to say it is a fair fight. Many of us who believe the user makes the biggest difference are likely to have our feelings hurt in this thread, because unbiased render engines in the right hands can and will outperform even the most gifted biased render artist. Honestly, this is not a fair fight.
Unbiased rendering isnt about artistry, its about pure mathematics. This thread is not addressing that point. Artistry is good at creating distractions, forcing the viewer to pay more attention to the things you want them to focus on in hopes they might not notice other things. Unbiased rendering one need not worry about that.
In time, all rendering will likely be unbiased. Just the way it goes.
The secret to realism is one word….Interaction. The more the given elements of a render can interact with one another by casting shadows onto one another, reflecting colors onto one another, transmitting one another…these interactive effects create a world that is believable. Placing point lights/ area lights etc to fill in surface bounces that arent actually happening within the render engine can create very good looking renders, but they still arent physically accurate, so the believability doesnt really matter..