This sample code demonstrates how to enumerate over all polygons on the active mesh layer, and print the material tag assigned to each polygon to the event log.

printMeshTags.py

#python

'''
  This sample code demonstrates how to enumerate over all polygons on the active
  mesh layer, and print the material tag assigned to each polygon to the event
  log.
'''

import lx
import lxu.command

class Command(lxu.command.BasicCommand):
	def __init__(self):
		lxu.command.BasicCommand.__init__(self)

	def cmd_Execute(self, msg):
		'''
		  The Layer Service allows us to read active, primary or
		  background layers. In this case, we want the primary layer,
		  which is the most recently selected mesh item.
		'''
		layerService = lx.service.Layer()
		layerScan = layerService.ScanAllocate(lx.symbol.f_LAYERSCAN_PRIMARY)
		
		'''
		  The number of layers should be 1 or 0, but we'll loop over
		  them all, allowing the code to easily be modified to work on
		  multiple active layers.
		'''
		layerCount = layerScan.Count()
		for i in range(layerCount):
			'''
			  The Base Mesh is the uneditable mesh in the base of
			  procedural stack. Similar functions exist for getting
			  an editable mesh, or the final result from the
			  procedural system.
			'''
			mesh = layerScan.MeshBase(i)
			polygonCount = mesh.PolygonCount()
			if polygonCount > 0:
				'''
				  Polygons are accessed using an accessor. When
				  polygons are "selected", the accessor is
				  modified to point at the "selected" polygon.
				  Note: The polygon is not selected by the
				  selection system, but just made active.
				  The PolygonAccessor also provides a StringTag
				  interface which can be used for querying tags.
				'''
				polygonAccessor = mesh.PolygonAccessor()
				stringTag = lx.object.StringTag(polygonAccessor)
				for j in range(polygonCount):
					polygonAccessor.SelectByIndex(j)
					materialTag = stringTag.Get(lx.symbol.i_PTAG_MATR)
					lx.out("Polygon: %d - Material: %s" % (j, materialTag))

lx.bless(Command, "mesh.printTags")