Is it possible to create and set a mtoa_constant_* attribute on a maya transform node and have Arnold use it for shading all the shape nodes underneath that transform? The ass files do not show any of the transform nodes in the hierarchy or reflect any of the attributes on the transforms.
Maybe related: I was hoping to be able to set the attribute anywhere in the hierarchy and have all the aiStandIn nodes below pick up the value. It only seems to work when the attribute is set on the aiStandIn shape node itself. Is that expected?