The Override node is very powerful but must be used with care. It allows you to override the value of any parameter of any Arnold node, whether it's in the .ass file or generated at render time by a procedural. You can have several overrides defined in the same Houdini node and several override nodes.

These nodes are experimental and may change or be removed without notice. It is advised that they are only for experienced users.

Arnold Node

The name of the node. Most of the time this will be the same as the absolute path of the node in Houdini but situations occur where it will be different. The name should be as it is written in the .ass file and should be obtained from there. For example, sphere_object1 in a houdini scene translates as /obj/sphere_object1/sphere1:polygons.

 name /obj/sphere_object1/sphere1:polygons
 nsides 90 1 b85UINT

Name of the Parameter to override. The Parameter Type can be chosen to allow easy input in the UI. Note that the actual value is passed into the .ass as a string regardless of the parameter type.


A simple scene has a subdivided sphere, with 1 iteration. A red wireframe in polygon mode is applied.


The override node is added with the values below.


Which results in the following render.


The overrides are appended to the end of the .ass file.

 /obj/sphere_object1/sphere1:polygons subdiv_iterations 3
 /shop/sphere_vopnet/wireframe1 fill_color 0.0 0.9 0.0
 /shop/sphere_vopnet/wireframe1 edge_type triangles



The Include OBJ node exposes the include directive to include an .ass file within an .ass file. It will write include directives at the end of exported .ass file, in order:

include "/home/user/Documents/HtoA/scenes/Overrides/include_cube.ass"
include "/home/user/Documents/HtoA/scenes/Overrides/include_sphere.ass"
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