Maya Functions - Removing Plug-in Nodes

To disable or unload a plug-in in maya could be tricky. I had situations when a plug-in could not be unload even if I pushed the 'Force' button on the poping window in Plug-In Manager because nodes of a certain plug-in was in use.

It seems maya can't always (or never) delete nodes that are in use. I had situations when maya crashed when I was loading a scene file which contained unknown nodes (unknown plug-in nodes). Actually I had to find out that the reason of the crashing is that a certain plug-in was not installed on my computer. Scene with Arnold nodes can produce crash when you want to load into a maya without installed Arnold plug-in.
So there is a need to delete plug-in nodes manually...or with a python script.

The main command is:

 cmds.pluginInfo("Mayatomr", q = 1, dependNode = 1)  

With argument "Mayatomr" it will list all the Mental Ray plug-in nodes. Or "mtoa" would list all Arnold specific nodes. Of course even if the plug-in is loaded this command returns something only if there is at least one node of that plug-in in the current maya scene.

Here is a function for removing plug-in specific nodes:

 def RemovePluginNodes(PlugIn = "mtoa", Verbose = 1):  
     '''  
     DESCRIPTION  
     Remove nodes of the given plug-in.  
     INPUT ARGUMENTS  
     - string - PlugIn - Name of the plug-in. You can check the exact (maya) name of the plug-in in the Maya Plug-in Manager. 
                         For eg.: Mental Ray plugin file: Mayatomr.mll -> "Mayatomr"  
     - int - Verbose - provide extra information about the process  
     RETURN  
     None  
     '''  
     plugInNodeTypeList = cmds.pluginInfo(PlugIn, q = 1, dependNode = 1)  
     for plugInNodeType in plugInNodeTypeList :  
         existingPlugInNodeList = cmds.ls(type = plugInNodeType)  
         if existingPlugInNodeList:  
             cmds.delete(existingPlugInNodeList)  
             if Verbose:  
                 print "Deleted nodes:\t%s" % existingPlugInNodeList  

I haven't tested extensively so give it a try and let me know your experience.