Solid Angle’s Arnold


Yes, it is named after Arnold Schwarzenegger. Until recently, the Arnold renderer has been curiously unavailable unless you had the secret code word – even the official website was just a blank page with a formula on it. And documentation? Don’t hold your breath. But the great thing is, Arnold is built with the artist in mind – so much so that you may not even need documentation. While being heavy on power and accuracy, it’s amazingly light on user interface and dials and knobs.

Now with a fancy new website, Arnold has entered the mainstream of rendering contenders as is already an industry heavy-hitter. At it’s heart, Arnold is raytracer, but a real efficient one. As raytracing is traditional slow and expensive, the engineers behind the curtain work everyday to squeeze as much efficiency and speed out of as few rays as possible. One of the reasons they can squeeze this engine so much is that they admit, it’s not for everyone. Focused solely on movies, Arnold doesn’t have a lot of code overhead to support other industries like architectural or automotive design. It is worth nothing again that to halve the noise one needs to quadruple the number of rays sampling, which makes the technical and speed achievements of Arnold all the more impressive.

Renderer_Arnold_SSSCheck out the amazing render to the right from Ubisoft Entertainment. Without using point clouds, Arnold now solves the sub-surface scatter (SSS) problem using raytracing and the results are phenomenal.

What does this mean? Without complex point clouds, SSS solutions are achieved faster, with less memory overhead, and better interactivity for the lighting artists. You can also start rendering multiple human faces in the same scene at the same time without melting your procs.

Some more of the features that make Solid Angle’s Arnold the envy of other engines:

Improved Importance Sampling
If you’re sampling a flat rectangle on a spherical object, the rectangle is actual curved – this is called the solid angle (sound familiar?). By sampling this solid angle instead of the original flat rectangle, you are sampling more effectively which in turn equates to less noise in the render.

Better Multi-Threading Capability
The engineering geniuses at Solid Angle take multi-threading very seriously. An efficient system is only as fast as it’s smallest bottleneck. When some VFX scenes can have many gigs of high resolution textures, that system bus still has to hit the hard drive and load them up as needed. This is a place where Arnold even trumps Renderman. While render time equals money and nodes are getting more and more procs all the time, creating a superhighway to transport data is paramount.