Well, if we use the MEL or pyhton command ls -type "lambert" we get more than just lambert shaders (if there are others in the scene). The reason is that the lambert shader has a type name which is the type for eg. blinn and phong are inherited from. The class hierarchy or inheritance diagram looks like this.
We can get this from the maya API documentation but we can query via MEL or python commands.
The following line gives us the inheritance diagram of "blinn1" shader as a list:
cmds.nodeType("blinn1", inherited = 1)
# Result: [u'shadingDependNode', u'lambert', u'reflect', u'blinn'] #
As we can see the items are similar but not the same. That is why because MEL and python scripts not work with C++ API names. If we look up blinn node from the nodes list of the technical documentation area we can see the parents field:
cmds.ls(type = "shape")
Or we can filter all the geometry type shapes, like curves, nurbs surfaces, meshes:
cmds.ls(type = "geometryShape")
So answering the first question: we can filter lambert shaders if we list lambert type with ls than check the exact type with nodeType command.
lambertTypeMaterialList = cmds.ls(type = "lambert")
lambertMaterialList = []
for item in lambertTypeMaterialList:
if cmds.nodeType(item) == "lambert":
lambertMaterialList.append(item)
# Result: [u'lambert1', u'lambert2'] #
With python set we can achieve useful functions easily. I wrote a function to check two or more objects' common type. I hope it works well.
def GetCommonClass(SelectedNodeList):
'''
== DESCRIPTION ==
Get the common type of the passed object list which is the first item in the inheritance diagram.
For eg. if we test a directionalLight and a nurbsCurve type nodes together the inheritance diagram are like this:
[u'containerBase', u'entity', u'dagNode', u'shape', u'geometryShape', u'deformableShape', u'controlPoint', u'curveShape', u'nurbsCurve']
[u'containerBase', u'entity', u'dagNode', u'shape', u'light', u'renderLight', u'nonAmbientLightShapeNode', u'nonExtendedLightShapeNode', u'directionalLight']
And we can see the first common type is the 'shape'.
== INPUT ARGUMENTS ==
+ list - SelectedNodeList - Maya node list
+
== RETURN ==
string - the first common type
== DEPENDENCIES ==
- maya.cmds
-
'''
if SelectedNodeList:
nodeTypeList = []
nodeTypeSet = set()
for item in SelectedNodeList:
nodeTypeList = cmds.nodeType(item, inherited = 1)
print nodeTypeList
if len(nodeTypeSet) != 0:
nodeTypeSet.intersection_update(set(nodeTypeList))
if len(nodeTypeSet) == 0:
print "There is no common type within selection."
return None
else:
nodeTypeSet.update(set(nodeTypeList))
commonTypeIndexList = []
for commonType in nodeTypeSet:
commonTypeIndexList.append(nodeTypeList.index(commonType))
firstCommonType = nodeTypeList[sorted(commonTypeIndexList)[-1]]
return firstCommonType
else:
return None
