Query an AOV existence in Maya

Question

I'm trying to write a script that makes it easier to create Light AOV's using LPE's (Light Path Expressions). But I just can't find a way to query the existence of previously created AOV's and skip those.

I'm following a tutorial I found from Arvid Schneider so some steps are from his video.

Here is what I have so far:

custAovLst = []  

for lightSel in range(len(LightList)):
    lgt_name = cmds.listRelatives(LightList, shapes = 1)
    aov ='setAttr -type "string" {}.aiAov {};'.format(lgt_name[lightSel], 'lgt_' + lgt_name[lightSel].replace("Shape", ""))
    mel.eval(aov)

for light in LightList:
    aovName = cmds.getAttr(light + '.aiAov')
    custAovLst.append(aovName) 


def aovCreate():
    for aovPass in custAovLst:
        if cmds.attributeQuery(aovPass , node = ".aiAov", ex = True):
            pass
        else:
            lightAov = aovs.AOVInterface().addAOV(aovPass, aovType='rgba')       
            aiAov = pmc.PyNode(lightAov.node)
            aiAov.lightPathExpression.set("C.<L.'" + aovPass + "'>.*")


aovCreate()

Any help or advice on how to achieve this or a better way to go on hits is more than welcome!

Answer 1

I ended up using a list with referenceQuery command.

aovList = cmds.ls(type = "aiAOV")
deleteNode = [node for node in aovList if 'lgt' in str(node) if not 
             cmds.referenceQuery(node, inr = 1)]
cmds.delete(deleteNode)