Arnold

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"Arnold is an advanced Monte Carlo ray tracing renderer built for the demands of feature-length animation and visual effects movies."

Introduction

Arnold is a ray tracing renderer by Solid Angle and is now a built-in plugin in Maya. It was developed as a photo-realistic, physically-based ray tracing alternative to traditional scanline based rendering software for CG animation. Generally, it consists of the following tools:

  • A ray server for traditional scanline renderers
  • A tool for baking/procedural generation of lighting data (lightmaps for videogames)
  • An interactive rendering and relighting tool

Using Arnold in Maya (MtoA)

MtoA is a plugin integrating Arnold into Maya. It comes with the shader nodes, lights as well as a renderview window to accelerate the lighting process.

MtoA is usually a built-in component so that you do not need to install anything else.

The MtoA is intergated well with the Maya workflow so most of the rendering options remain the same for Arnold.

Using Arnold in Houdini (HtoA)

HtoA is a plugin intergating Arnold into Houdini. It comes with a shader system which is not compatible with Houdini's shader nodes directly. It is also integrated with the Houdini workflow but without support for some volume or effect renderers.

HtoA can be installed from Arnold's website.

Creating Materials

Arnold's material system is a straightforward system which features physically based shading. It uses a multiple layer design by default to support coats, sheens, reflective and many other render options.

Setting Up Lights

Arnold is shipped with a variety of lights including area lights, skydome lights and more. The area acts more like real lights and the skydome light provides a good support for the environment ambience. Some of the lights in Maya are not supported in Arnold, and you can check here for more details.

Noise and Fireflies

Because Arnold is a ray tracer, it usually needs a pretty high sample count to reduce the noises. Similarly, sometimes the specular settings will cause fireflies which are hard to eliminate.

As a guide, you can check Removing Noise as a starting point. It needs a lot of practice to handle it well and remember that the artists' time is worth more than machines' time.