OPmenu.xml

<?xml version="1.0" encoding="UTF-8"?>
<menuDocument>
     <menu>
            <!--***********************************-->
            <scriptItem id="saveMatToEgLib">
                <context>
                    <expression>
<![CDATA[
n = kwargs.get("node", None)
if n.type().name() == "redshift_vopnet":
    return True
elif n.type().name() == "octane_vopnet":
    return True
elif n.type().name() == "materialbuilder":
    return True
elif n.type().name() == "principledshader::2.0":
    return True
elif n.type().name() == "arnold_materialbuilder":
    return True
return False ]]>
                    </expression>
                </context>
                <labelExpression>
<![CDATA[
n = kwargs.get("node", None)
if n.type().name() == "redshift_vopnet":
    return "Save Material to MatLib"
elif n.type().name() == "octane_vopnet":
    return "Save Material to MatLib"
elif n.type().name() == "materialbuilder":
    return "Save Material to MatLib"
elif n.type().name() == "principledshader::2.0":
    return "Save Material to MatLib"
elif n.type().name() == "arnold_materialbuilder":
    return "Save Material to MatLib"
return "Unavailable in this Context"
]]>
                </labelExpression>
                <scriptCode>
<![CDATA[
n = kwargs.get("node", None)
if n.type().name() == "redshift_vopnet":
    import egMatLib
    egMatLib.saveMaterial(n)
elif n.type().name() == "octane_vopnet":
    import egMatLib
    egMatLib.saveMaterial(n)
elif n.type().name() == "materialbuilder":
    import egMatLib
    egMatLib.saveMaterial(n)
elif n.type().name() == "principledshader::2.0":
    import egMatLib
    egMatLib.saveMaterial(n)
elif n.type().name() == "arnold_materialbuilder":
    import egMatLib
    egMatLib.saveMaterial(n)
else:
    hou.ui.displayMessage('Please select Material Builder Nodes to save Material')

]]>
                </scriptCode>
            </scriptItem>
                            <!--***********************************-->
    </menu>
</menuDocument>