engine of choice for exteriors and scenes where direct lighting is dominant. Nevertheless, it also responds nicely in
relatively difficult indirect lighting cases.
In the previous weeks, we worked hard to make TR1 even more powerful for indirect lighting cases. The result of our
deep research, testing and development is the evolution of TR1 (codenamed "TR1+" in our interior builds) into a method
that manages extremely well under indirect lighting conditions, while keeping 100% its power in exteriors and direct
lighting. Surely, there is no "holy grail" unbiased engine (i.e. an engine that delivers best performance in all kinds of
scenes), but the improved TR1 is as close as possible to this definition.
Getting more technical on this, "TR1+" is able to handle much better dark areas in your renders, that "traditionally" take
more time to resolve. This way, it delivers a more balanced noise and an image that overall converges faster. For
exteriors and dominant direct lighting scenes the performance is the same as before, but in more difficult cases, like
interiors lit by sun-sky, TR1+ is a clear winner. We estimate that the efficiency improvement of TR1 can be up to 70%!
For extremely difficult cases, like rooms lit by caustic lighting, or heavy indirect caustics, TR2 should still be the method
of choice, though.
We are really happy and proud for this achievement, something, we believe, that makes Thea unbiased core the most
sophisticated around. Below, we give some test cases that show Thea unbiased core strength. For comparison
purposes, we use the codename "TR1+" for the enhanced version, but in the forthcoming public revision TR1+ will
replace TR1.
Church Interior: Designed and Rendered by Tomasz Marek
We can see below a church interior; the difficulty here is that there is a huge dynamic range in the image, with areas of
strong incident lighting and other very dark areas. TR1+ is the clear winner here, delivering the most balanced image -
noise wise - for the human eye. Note: images are cycled every 4 seconds to see better the difference.
- Animated gif showing renders of TR2, TR1 and TR1+. Scene modeled and rendered by Tomasz Marek.
- Interior_by_TomaszMarek_10m_DualCore.gif (503.52 KiB) Viewed 17794 times
A relatively heavy scene, lit by sun-sky. Not an easy thing, and there are a lot of dark areas - difficult for sun/sky light
to reach. The enhancement of TR1+ versus TR1 is shown clearly in the image below. Note: images are cycled every 4
seconds to see better the difference.
- Animated gif showing renders of TR1 and TR1+. Scene modeled by Alvaro Luna Bautista and Joel Andersdon.
- NaturalHistoryMuseum_by_AlvaroLunaBautista_JoelAndersdon_15m_1Thread_i5_2.66Ghz.gif (495.02 KiB) Viewed 17794 times
Another typical interior lit by sun-sky. Again, TR1+ boost is clearly visible. Note: images are cycled every 4 seconds to
see better the difference.
- Animated gif showing renders of TR1 and TR1+. Scene rendered by Pete Stoppel.
- Interior_by_PeteStoppel_18m_i7.gif (505.84 KiB) Viewed 17794 times
Here is a difficult indirect lighting test scene. In this scene, there are 2 rooms and we can only see the right room, from
the top, which is open. An emitter is present in the left room, which is blocked by a larger occluder. Light has to bounce
back and find its way through the small holes on the floor to reach the right room. Comparisons with other unbiased
renderers, show full superiority of Thea TR1 (note that TR2 is able to render this case even faster)!
- Indirect lighting setup by Claudio Pilustrelli. Area emitter is blocked, while lighting goes in next room from the small holes on the floor. Rendered by TR1+ for 10 min, on single thread of dual-core 1.66Ghz.
- IndirectLightTest_by_ClaudioPilustrelli_TR1+_10m_1Thread_DualCore1.66Ghz.jpg (131.67 KiB) Viewed 17794 times
