Pete Hanshaw: PyMel- Getting texture file from a material

So, my first inelegant-yet-functional PyMel script is done and working. The core of it is in this little snippet here, that digs through a mesh's inputs until it finds the texture node on the surface shader:

#Pass through the mesh's shape and return a texture name. 
import pymel as pm

def getTextureFile(geo):

    sg = []

    #Get the shading group from the selected mesh
    raw_sg = pm.listConnections(geo, type='shadingEngine')

    #Rapidly check for duplicates in the list- I do this by checking each item 
    #against an empty list. 
    #If the item is not in the empty list I append it. 
    
    for element in raw_sg:
        if element not in sg:
            sg.append(element)

    #Get some info
    sgInfo = pm.listConnections(sg[0], type='materialInfo')
    fileNode = pm.listConnections(sgInfo[0], type='file')
    textureFile = pm.getAttr(fileNode[0].fileTextureName)



    print 'This is the file', str(textureFile)
    return str(textureFile)

It still leaves a lot to be desired, for instance it doesn't know what to do if a mesh doesn't actually have a texture! But, provided it does, using the win32com module I can then send the texture file information onto Photoshop and Alienbrain and open files/check out texture chains etc etc.

EDIT:
------------------------------------------------------------------------------------------------------------
Thanks to Daydreamer who pointed out the missing pymel reference at the top of the snippet, as well as other issues with the script which I am working through...

After a happy weekend of actually reading part of the official tutorial, I have a slightly better understanding of how to access a mesh's attributes and nodes using PyMel. Here is a snippet of the above snippet that does pretty much the same thing, only using the pymel connections, input and output commands. The intention is only to test the functionality.

    
    import pymel as pm

    geo = pm.ls(sl=True)[0].getShape()

    #Get the shading group from the selected mesh
    sg = geo.outputs(type='shadingEngine')

    #Work through the node to get the file texture name
    sgInfo = sg[0].connections(type='materialInfo')
    
    #It falls apart here if you have no file node! Oops...
    fileNode = sgInfo[0].connections(type='file')

    #Get the file texture name attribute's value
    textureFile = pm.getAttr(fileNode[0].fileTextureName)

    print 'This is the file', str(textureFile)

4 comments:

Day DreamerAugust 31, 2012 at 10:59 PM
Hi Pete,
nice.....

but, u can improve this snippet many folds.

eg.

In section

A. # Clean up the list(which looks misleading)
1. use list comprehension instead of normal loop. it will run faster then normal loop and u dont have to declare sg variable in advance.

2.it seems u r creating a new list named sg frm raw_sg, u can du thz by using deepcopy function or usin slicing.

B. #Pass through the mesh's shape and return a texture name. and #Get some info

1. Where is PyMel??
just using "pm" doesn't mean PyMel, don't u think if i use "cmds"(python in maya) instead of "pm" it will be exactly the same. where is OOP?

C. This code will also starts failing if my variables values are None. In simple, if i don't have texture over my selected mesh.
You need to add checks or validations.

Need more elaborate discussion, write in to me.
Or drop comment on my site.

Regards
Day Dreamer
www.daydreamer3d.weebly.com

Day DreamerSeptember 9, 2012 at 4:59 AM
# Note:- ____ means whitespaces

import pymel as pm

# Check selection
sel = pm.ls(sl=True)
if not sel:
____print 'Selection is empty. Kindly select a geometry.'
____# if under function return here

# Assuming you are interested in single selected object
# (generally, i prefer last selected object, Maya Way)
# re-defying "sel" variable with just last object
sel = sel[-1]

geo = sel.getShape()

# Checking selected object is a mesh(shape)
if not geo:
____print 'No Shape Found For %s' % sel
____# if under function return here

#Get the shading group from the selected mesh
sg = geo.outputs(type='shadingEngine')
if not sg:
____print 'No Shading Engine Exists For %s' % geo
____# return here

#Work through the node to get the file texture name
sgInfo = sg[0].connections(type='materialInfo')

#It falls apart here if you have no file node! Oops...
fileNode = sgInfo[0].connections(type='file')
if not fileNode:
____print 'No Texture Exists For %s' % geo
____# return here

#Get the file texture name attribute's value
#textureFile = pm.getAttr(fileNode[0].fileTextureName)
textureFile = fileNode[0].fileTextureName.get()

if not textureFile:
____print 'No Texture Path Found For:-\n\t\tShape:- {0}\n\t\tTexture:- {1}'.format(geo, fileNode[0])
____return here

print 'This is the file %s' % textureFile
UnknownMarch 14, 2013 at 3:24 AM
Why not remove duplicates in your list by simply doing a my_list = list(set(my_list))

-Sven

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