The goal here is to compare 3Delight's OSL rendering core with other renderers using C++ for shading (namely Arnold and RenderMan RIS). Since all renderers are quite different, we will try to get to a most common denominator, in terms of setup, to be able to compare apples to apples. We want to know: can we go as fast, in OSL, as highly optimized C++ ray-tracer ? How does OSL compare to ours our optimized RSL , SIMD just-in-time compiler ?
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Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 16 On-line CPU(s) list: 0-15 Thread(s) per core: 2 Core(s) per socket: 4 Socket(s): 2 Vendor ID: GenuineIntel CPU family: 6 Model: 26 Stepping: 5 CPU MHz: 2395.000 BogoMIPS: 4787.24 Virtualization: VT-x L1d cache: 32K L1i cache: 32K L2 cache: 256K L3 cache: 8192K |
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% free -m
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total used free shared buffers cached Mem: 11984 8139 3844 0 151 4728 -/+ buffers/cache: 3259 8725 Swap: 0 0 0 |
The Setup
Each Each renderer uses a different sampling strategy and how rays are distributed between each sampled component. We selected a setup that produces nearly the same number of rays in all renderers. Look wise, it was easy to obtain very similar renders between Arnold and 3Delight. We had to boost area light contributions in order to get a similar lighting in RenderMan/RIS.
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Render time is almost identical, 34 seconds for the entire render. Performance penalty is almost nil.
Conclusion
- 3Delight's OSL-based path-tracer provides outstanding performance results. Building a rendering core around the OSL shading system, as opposed to just "integrating" OSL in the renderer, seems to have given 3Delight a good performance advantage.
- Multi Light in 3Delight doesn't have a perceptible adverse effect in this test (although from experience, rendering much more Multi Light AOVs, one can expect a 1-3% penalty).
- This particular test shows the limitations of RSL shaders and the limitations of the JIT architecture
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- they use.
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Resources
Here are the links to reproduce the tests on your system.
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