Arnold Procedural

To load the geometry, you need to create an Arnold Procedural object. Go to Plugins > C4DtoA > Arnold Procedural and specify the Type of the procedural and the archive to be used.

Procedurals are supported via the Arnold Procedural node


In addition to archive ASS (.ass, .obj, .ply), Alembic (.abc) or USD files, pre-compiled custom procedural plugins can also be selected here (e.g. the Mandelbulb procedural), though none are shipped with C4DtoA currently.



Defines the length unit of the loaded archive. Different DCCs work in different units, for instance the default unit in Maya is 1 cm, while in Houdini it's 1 m. 

Display Bounding Box

Reads the bounding box from the Geometry File.

Object Display Mode

Viewport Proxy

Enable this option to reduce the number of points and polygons displayed in the viewport.

Proxy Tolerance

Viewport proxy objects are generated via the ''Optimize Mesh'' command which requires a Tolerance input. If points are closer to each other than this value, then they are merged into one point. If the points are further apart than the value, they will not be merged. If polygons become redundant (e.g., if all three corner points of the polygon occupy the same point), they will be removed. 

Create Objects

If enabled the Arnold Procedural object behaves as an object generator, and geometries of the procedural will be generated to the scene as Poly objects.

You can use the Make object command (press c) to turn the procedural to actual polygon objects if this option is enabled.

View Content

Opens a dialog that displays the content of the procedural as a node tree. You can copy the name of an object and paste it to the selection expression of the parameter overrides (see below).



Choose to 'mute' or 'disable' various rendering options for selected Arnold Procedurals. This will override the values set within the procedural file. 'Mute' (set by default) uses the values set within the procedural file.

User Options

This string field can be set to override any parameter of the Arnold procedural node. For more info see User Options.

Parameter Overrides

These options allow you to override any parameters of the Arnold nodes (shapes, shaders, lights, etc.) created by the procedural object. See this tutorial for more details.


Specify the parameter override mode, selecting from the following:

Number of parameter overrides

Define the number of override expressions applied to the given procedural.


Enables the override.


Specify the name of the Arnold node which you want to override. Click on the button next to the input field to select a node loaded by the procedural. See the Operators page for more information on the selected expressions.

In case of an ASS procedural you can check the node names by opening the ASS file in a text editor.


Specify the mode of the override, selecting from the following:

MaterialX Export

These options allow you to export the current overrides (look) to a MaterialX document (.mtlx). The export is always relative, so you can assign the look to another procedural with a different name.






Procedurals can reference other assets in ASS files which are 'invisible' for C4DtoA. For example, if you have an object with a texture in your referenced ASS file, C4DtoA does not know anything about this texture and won't distribute it to the clients. In this case, you have to manually define these assets on the Assets tab.

It is important that you define the same paths here as they are in the ASS file. If the path is absolute in the ASS file, you must set an absolute path here. If only the file name is given, you must set the file name here as well. If you have a sequence in the ASS file, define it using padding (#) characters. This is because C4DtoA has to replace the path in the ASS file with the downloaded assets on the client machines. Note, that absolute paths do not work with ass.gz files.

You can also define folders in which case all files from the folders and subfolders will be transferred to the client machines. Note that this requires relative paths in the ASS file.

Instead of defining assets here, you can keep your assets in a shared folder and add the folder to the Texture Search Path in the Render Settings.