Toon shader: a non-photorealistic rendering (NPR) solution is provided as the combination of the contour filter and toon shader. The contour filter draws contour lines using the information provided by the toon shader and it works even for reflected or refracted objects. The toon shader can be used to obtain a cell animation look. A variety of interesting effects can be achieved by, for example, changing the line width using the Edge width scale parameter, connecting a procedural texture to Mask color, or using stylized highlights.
- Adaptive sampling: Arnold now has the capability of adapting the sampling rate of each pixel when the Enable adaptive sampling render option is enabled, allowing it to dedicate a greater number of camera samples (and thus also a greater amount of render time) to the pixels that show a greater variation in their sample values. When used, all pixels will receive a sampling rate of at least Camera (AA) samples, but no more than AA samples max. The adaptive sampler's sensitivity to noise may be controlled through the Adaptive threshold render option, where lower threshold values will apply higher sampling rates to a greater number of pixels.
- Denoiser (OptiX): the fast, GPU-powered Nvidia OptiX AI denoiser is now available in Arnold. The denoiser can be applied to any outputs. As a limitation, it does not work with multi-channel images. Note that the denoiser is not available on OSX.
- Denoiser (noice): a stand-alone, post-process denoiser executable called Noice is now bundled with Arnold. This is a high-quality denoiser that takes into account multiple frames and multiple light AOVs.
- Alembic procedural: a procedural node called alembic which is capable of reading Alembic .abc files has been added, available through the Arnold Procedural object.
- Operators: operators are a new node type which perform per-object (node) parameter assignments and overrides, including late-bindings and deferred overrides on procedurally generated nodes. Operators can also create nodes and carry out general scene inspection and modifications. Operators can be chained together in a graph which is evaluated from a given target operator. Some operators provide a selection parameter which determines, using a wildcard expression, what nodes are processed by the operator. A series of operator nodes are now available: materialx, set_parameter, disable, collection, switch_operator, and set_transform.
- Procedural overrides: a new section is added to the Arnold Procedural object, called Parameter Overrides, which allows users to override any parameters (e.g. shaders of individual polymeshes) of the Arnold nodes created by the procedural.
- New AOV write RGBA shader: the aov_write_rgba shader has been added which complements the existing RGB, float and int variations of this shader.
- Structured statistics: render statistics can now be output to JSON files at the end of each render pass, either appended to or overwriting an existing .json file. This is much easier for tools to inspect rather than attempt to parse out the raw-text statistics in the logs that were meant for human consumption.
- Better time statistics: additional timing statistics, organized by both nodes and categories, will now be output. This makes it possible to know which objects are most expensive to render and what parts of the renderer took the most amount of time. Detailed information about rendering performance can be output to a file in JSON format, such as "my_profile.json", and then visualized in Google's Chrome web browser "chrome://tracing/".
- Progressive refinement (EXPERIMENTAL): a new rendering mode that completes a render call in multiple passes has been added to the IPR window. When enabled the noise progressively converges towards the result at the final AA sample settings. Note that, in its current unoptimized state, the final passes can take very long to filter at high AA samples. This will be addressed in a future update.
- The Optix denoiser is only compatible with a Nvidia driver version of at least 390 installed.
- The Optix denoiser is not available on OSX.
- There are modifications in the C4DtoA API which require third-parties to recompile their C4DtoA extensions.