Arnold Procedural - Arnold User Guide
Duck model exported as .ass file and imported as a procedural
You can export any object as a .ass file. A procedural (also called stand-in, proxy or placeholder) references the .ass file on disk (or other procedural formats supported by Arnold such as .obj or .ply). They allow you to keep your working scene light and workable by deferring the loading of geometry data until render time.
The utility shader's object mode does not work with procedurals (stand-ins). This is a known limitation. The color of the spheres changes when the utility shader's mode is object. However, the procedural color remains the same.
Spheres Arnold Procedural
Some users may be in a studio environment where a combination of Maya, 3DS Max, Houdini, and C4D are used. It is perfectly possible to export .ass Arnold Procedurals (stand-ins) and reuse them in other Arnold plug-ins (and vice versa), as long as Arnold can find both the plug-in and shaders. To do this, you must ensure that the Arnold shader path environment variable ARNOLD_PLUGIN_PATH is set to pick up both sets of shaders.
File/Frame
Procedurals are supported via the procedural node. This node has the following parameters:
Path
The path to the archive (.ass) file. There is an automatic sequence recognition in the case of an archive.
The padding patterns have this form:
- name.#.ext - e.g. name.1.ext, name.2.ext, name.3.ext, ..., name.10.ext, ..., name.100.ext, ...
- name.##.ext - e.g. name.01.ext, name.02.ext, name.03.ext, ..., name.10.ext, ..., name.100.ext, ...
- name.###.ext - e.g. name.001.ext, name.002.ext, name.003.ext, ..., name.010.ext, ... , name.100.ext, ...
- name####.###.ext - indicates four digit padding for frame numbers and three digit padding for sub-frame digits.
For example: If we point to a file called, test_001.ass it will be recognized as a sequence pattern in the form of test_###.ass. If you want to override the automatic sequence recognition, we can manually change the path string and remove the padding pattern with the corresponding filename.
File Sequences
Frame
The frame to read that will replace the pattern defined in the Use Frame Extension checkbox.
Frame Offset
Offset to the current frame. This allows the same animation sequence to be used while creating different procedurals.
Override Nodes
Nodes inside the procedural can be replaced by other nodes with this parameter. This may be used for example to replace shaders in an existing .ass procedural. When the parameter is enabled, nodes in the immediate parent scope of the procedural will replace identically named nodes inside the procedural.
Namespace
Procedurals can declare a custom namespace using this parameter. This custom namespace can be used instead of the procedural name, to reference contents through absolute or relative paths. Multiple procedurals can share the same namespace by using the same custom name. Also, they can declare an empty name and they will use the global namespace.
User Options
This string field can be set to override any parameter of the Arnold procedural node.