Removing MtoA from Maya scenes

If you don’t use Arnold, but someone has saved your scene files with MtoA loaded, then you’ll get some errors and warnings when you open that scene without MtoA.

// Error: line 0: The camera 'perspShape' has no 'ai_translator' attribute. // 
// Error: line 0: Node "perspShape" has no attribute "ai_translator". // 
// Error: line 0: The camera 'topShape' has no 'ai_translator' attribute. // 
// Error: line 0: Node "topShape" has no attribute "ai_translator". // 
// Error: line 0: The camera 'frontShape' has no 'ai_translator' attribute. // 
// Error: line 0: Node "frontShape" has no attribute "ai_translator". // 
// Error: line 0: The camera 'sideShape' has no 'ai_translator' attribute. // 
// Error: line 0: Node "sideShape" has no attribute "ai_translator". // 
// Error: line 0: The mesh 'pPlaneShape1' has no 'ai_translator' attribute. // 
// Error: line 0: Node "pPlaneShape1" has no attribute "ai_translator". // 
// Error: line 0: The mesh 'pSphereShape1' has no 'ai_translator' attribute. // 
// Error: line 0: Node "pSphereShape1" has no attribute "ai_translator". // 
// Error: line 0: The mesh 'pCubeShape1' has no 'ai_translator' attribute. // 
// Error: line 0: Node "pCubeShape1" has no attribute "ai_translator". // 
// Warning: line 0: Unrecognized node type for node 'defaultArnoldRenderOptions'; preserving node information during this session. // 
// Warning: line 0: Unrecognized node type for node 'defaultArnoldFilter'; preserving node information during this session. // 
// Warning: line 0: Unrecognized node type for node 'defaultArnoldDriver'; preserving node information during this session. // 
// Warning: line 0: Unrecognized node type for node 'defaultArnoldDisplayDriver'; preserving node information during this session. //

Here’s how to remove all the MtoA (aka Arnold) attributes and nodes.

First, don’t load MtoA. Uninstall MtoA.

Now, just loading and saving your scene will get rid of the ai_translator attributes. All that’s left to do is get rid of the unknown nodes. There’s just four (assuming nobody created any Arnold shaders or lights or standins in the scene): the four defaultArnold nodes:

ls -typ "unknown";
// Result: defaultArnoldDisplayDriver defaultArnoldDriver defaultArnoldFilter defaultArnoldRenderOptions //

Here’s a MEL script to remove all unknown MtoA nodes from a scene:

string $mtoaNodes[] = `ls -typ "unknown"`;

for ($node in $mtoaNodes){
	if (`objExists $node` && `unknownNode -q -p $node` == "mtoa"){
		print("Deleting mtoa node " + $node + "\n");
		delete $node;
	}
}