blender/release/scripts/export_obj.py
Campbell Barton 345866b61e Fix for [#8382] UV unwrap & export puts seams on all edges.
Maya uses OBJ's UV's to generate seams, some people complained that models imported from blender didnt work well in maya.
It was faster to write every faces UV (without doing a remove doubles), but sharing UV coords makes smaller files and might also be more efficient in other applications.
2008-02-27 23:10:25 +00:00

678 lines
22 KiB
Python

#!BPY
"""
Name: 'Wavefront (.obj)...'
Blender: 243
Group: 'Export'
Tooltip: 'Save a Wavefront OBJ File'
"""
__author__ = "Campbell Barton, Jiri Hnidek"
__url__ = ['www.blender.org', 'blenderartists.org']
__version__ = "1.1"
__bpydoc__ = """\
This script is an exporter to OBJ file format.
Usage:
Select the objects you wish to export and run this script from "File->Export" menu.
Selecting the default options from the popup box will be good in most cases.
All objects that can be represented as a mesh (mesh, curve, metaball, surface, text3d)
will be exported as mesh data.
"""
# --------------------------------------------------------------------------
# OBJ Export v1.1 by Campbell Barton (AKA Ideasman)
# --------------------------------------------------------------------------
# ***** BEGIN GPL LICENSE BLOCK *****
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software Foundation,
# Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#
# ***** END GPL LICENCE BLOCK *****
# --------------------------------------------------------------------------
import Blender
from Blender import Mesh, Scene, Window, sys, Image, Draw
import BPyMesh
import BPyObject
import BPySys
import BPyMessages
# Returns a tuple - path,extension.
# 'hello.obj' > ('hello', '.obj')
def splitExt(path):
dotidx = path.rfind('.')
if dotidx == -1:
return path, ''
else:
return path[:dotidx], path[dotidx:]
def fixName(name):
if name == None:
return 'None'
else:
return name.replace(' ', '_')
# A Dict of Materials
# (material.name, image.name):matname_imagename # matname_imagename has gaps removed.
MTL_DICT = {}
def write_mtl(filename):
world = Blender.World.GetCurrent()
if world:
worldAmb = world.getAmb()
else:
worldAmb = (0,0,0) # Default value
file = open(filename, "w")
file.write('# Blender3D MTL File: %s\n' % Blender.Get('filename').split('\\')[-1].split('/')[-1])
file.write('# Material Count: %i\n' % len(MTL_DICT))
# Write material/image combinations we have used.
for key, (mtl_mat_name, mat, img) in MTL_DICT.iteritems():
# Get the Blender data for the material and the image.
# Having an image named None will make a bug, dont do it :)
file.write('newmtl %s\n' % mtl_mat_name) # Define a new material: matname_imgname
if mat:
file.write('Ns %.6f\n' % ((mat.getHardness()-1) * 1.9607843137254901) ) # Hardness, convert blenders 1-511 to MTL's
file.write('Ka %.6f %.6f %.6f\n' % tuple([c*mat.amb for c in worldAmb]) ) # Ambient, uses mirror colour,
file.write('Kd %.6f %.6f %.6f\n' % tuple([c*mat.ref for c in mat.rgbCol]) ) # Diffuse
file.write('Ks %.6f %.6f %.6f\n' % tuple([c*mat.spec for c in mat.specCol]) ) # Specular
file.write('Ni %.6f\n' % mat.IOR) # Refraction index
file.write('d %.6f\n' % mat.alpha) # Alpha (obj uses 'd' for dissolve)
# 0 to disable lighting, 1 for ambient & diffuse only (specular color set to black), 2 for full lighting.
if mat.getMode() & Blender.Material.Modes['SHADELESS']:
file.write('illum 0\n') # ignore lighting
elif mat.getSpec() == 0:
file.write('illum 1\n') # no specular.
else:
file.write('illum 2\n') # light normaly
else:
#write a dummy material here?
file.write('Ns 0\n')
file.write('Ka %.6f %.6f %.6f\n' % tuple([c for c in worldAmb]) ) # Ambient, uses mirror colour,
file.write('Kd 0.8 0.8 0.8\n')
file.write('Ks 0.8 0.8 0.8\n')
file.write('d 1\n') # No alpha
file.write('illum 2\n') # light normaly
# Write images!
if img: # We have an image on the face!
file.write('map_Kd %s\n' % img.filename.split('\\')[-1].split('/')[-1]) # Diffuse mapping image
elif not mat: # No face image. if we havea material search for MTex image.
for mtex in mat.getTextures():
if mtex and mtex.tex.type == Blender.Texture.Types.IMAGE:
try:
filename = mtex.tex.image.filename.split('\\')[-1].split('/')[-1]
file.write('map_Kd %s\n' % filename) # Diffuse mapping image
break
except:
# Texture has no image though its an image type, best ignore.
pass
file.write('\n\n')
file.close()
def copy_file(source, dest):
file = open(source, 'rb')
data = file.read()
file.close()
file = open(dest, 'wb')
file.write(data)
file.close()
def copy_images(dest_dir):
if dest_dir[-1] != sys.sep:
dest_dir += sys.sep
# Get unique image names
uniqueImages = {}
for matname, mat, image in MTL_DICT.itervalues(): # Only use image name
# Get Texface images
if image:
uniqueImages[image] = image # Should use sets here. wait until Python 2.4 is default.
# Get MTex images
if mat:
for mtex in mat.getTextures():
if mtex and mtex.tex.type == Blender.Texture.Types.IMAGE:
image_tex = mtex.tex.image
if image_tex:
try:
uniqueImages[image_tex] = image_tex
except:
pass
# Now copy images
copyCount = 0
for bImage in uniqueImages.itervalues():
image_path = sys.expandpath(bImage.filename)
if sys.exists(image_path):
# Make a name for the target path.
dest_image_path = dest_dir + image_path.split('\\')[-1].split('/')[-1]
if not sys.exists(dest_image_path): # Image isnt alredy there
print '\tCopying "%s" > "%s"' % (image_path, dest_image_path)
copy_file(image_path, dest_image_path)
copyCount+=1
print '\tCopied %d images' % copyCount
def write(filename, objects,\
EXPORT_TRI=False, EXPORT_EDGES=False, EXPORT_NORMALS=False, EXPORT_NORMALS_HQ=False,\
EXPORT_UV=True, EXPORT_MTL=True, EXPORT_COPY_IMAGES=False,\
EXPORT_APPLY_MODIFIERS=True, EXPORT_ROTX90=True, EXPORT_BLEN_OBS=True,\
EXPORT_GROUP_BY_OB=False, EXPORT_GROUP_BY_MAT=False, EXPORT_MORPH_TARGET=False):
'''
Basic write function. The context and options must be alredy set
This can be accessed externaly
eg.
write( 'c:\\test\\foobar.obj', Blender.Object.GetSelected() ) # Using default options.
'''
def veckey3d(v):
return round(v.x, 6), round(v.y, 6), round(v.z, 6)
def veckey2d(v):
return round(v.x, 6), round(v.y, 6)
print 'OBJ Export path: "%s"' % filename
temp_mesh_name = '~tmp-mesh'
time1 = sys.time()
scn = Scene.GetCurrent()
file = open(filename, "w")
# Write Header
file.write('# Blender3D v%s OBJ File: %s\n' % (Blender.Get('version'), Blender.Get('filename').split('/')[-1].split('\\')[-1] ))
file.write('# www.blender3d.org\n')
# Tell the obj file what material file to use.
if EXPORT_MTL:
mtlfilename = '%s.mtl' % '.'.join(filename.split('.')[:-1])
file.write('mtllib %s\n' % ( mtlfilename.split('\\')[-1].split('/')[-1] ))
# Get the container mesh. - used for applying modifiers and non mesh objects.
containerMesh = meshName = tempMesh = None
for meshName in Blender.NMesh.GetNames():
if meshName.startswith(temp_mesh_name):
tempMesh = Mesh.Get(meshName)
if not tempMesh.users:
containerMesh = tempMesh
if not containerMesh:
containerMesh = Mesh.New(temp_mesh_name)
if EXPORT_ROTX90:
mat_xrot90= Blender.Mathutils.RotationMatrix(-90, 4, 'x')
del meshName
del tempMesh
# Initialize totals, these are updated each object
totverts = totuvco = totno = 1
face_vert_index = 1
globalNormals = {}
# Get all meshs
for ob_main in objects:
for ob, ob_mat in BPyObject.getDerivedObjects(ob_main):
# Will work for non meshes now! :)
# getMeshFromObject(ob, container_mesh=None, apply_modifiers=True, vgroups=True, scn=None)
me= BPyMesh.getMeshFromObject(ob, containerMesh, EXPORT_APPLY_MODIFIERS, False, scn)
if not me:
continue
if EXPORT_UV:
faceuv= me.faceUV
else:
faceuv = False
# We have a valid mesh
if EXPORT_TRI and me.faces:
# Add a dummy object to it.
has_quads = False
for f in me.faces:
if len(f) == 4:
has_quads = True
break
if has_quads:
oldmode = Mesh.Mode()
Mesh.Mode(Mesh.SelectModes['FACE'])
me.sel = True
tempob = scn.objects.new(me)
me.quadToTriangle(0) # more=0 shortest length
oldmode = Mesh.Mode(oldmode)
scn.objects.unlink(tempob)
Mesh.Mode(oldmode)
# Make our own list so it can be sorted to reduce context switching
faces = [ f for f in me.faces ]
if EXPORT_EDGES:
edges = me.edges
else:
edges = []
if not (len(faces)+len(edges)+len(me.verts)): # Make sure there is somthing to write
continue # dont bother with this mesh.
if EXPORT_ROTX90:
me.transform(ob_mat*mat_xrot90)
else:
me.transform(ob_mat)
# High Quality Normals
if EXPORT_NORMALS and faces:
if EXPORT_NORMALS_HQ:
BPyMesh.meshCalcNormals(me)
else:
# transforming normals is incorrect
# when the matrix is scaled,
# better to recalculate them
me.calcNormals()
# # Crash Blender
#materials = me.getMaterials(1) # 1 == will return None in the list.
materials = me.materials
materialNames = []
materialItems = materials[:]
if materials:
for mat in materials:
if mat: # !=None
materialNames.append(mat.name)
else:
materialNames.append(None)
# Cant use LC because some materials are None.
# materialNames = map(lambda mat: mat.name, materials) # Bug Blender, dosent account for null materials, still broken.
# Possible there null materials, will mess up indicies
# but at least it will export, wait until Blender gets fixed.
materialNames.extend((16-len(materialNames)) * [None])
materialItems.extend((16-len(materialItems)) * [None])
# Sort by Material, then images
# so we dont over context switch in the obj file.
if EXPORT_MORPH_TARGET:
pass
elif faceuv:
try: faces.sort(key = lambda a: (a.mat, a.image, a.smooth))
except: faces.sort(lambda a,b: cmp((a.mat, a.image, a.smooth), (b.mat, b.image, b.smooth)))
elif len(materials) > 1:
try: faces.sort(key = lambda a: (a.mat, a.smooth))
except: faces.sort(lambda a,b: cmp((a.mat, a.smooth), (b.mat, b.smooth)))
else:
# no materials
try: faces.sort(key = lambda a: a.smooth)
except: faces.sort(lambda a,b: cmp(a.smooth, b.smooth))
# Set the default mat to no material and no image.
contextMat = (0, 0) # Can never be this, so we will label a new material teh first chance we get.
contextSmooth = None # Will either be true or false, set bad to force initialization switch.
if EXPORT_BLEN_OBS or EXPORT_GROUP_BY_OB:
name1 = ob.name
name2 = ob.getData(1)
if name1 == name2:
obnamestring = fixName(name1)
else:
obnamestring = '%s_%s' % (fixName(name1), fixName(name2))
if EXPORT_BLEN_OBS:
file.write('o %s\n' % obnamestring) # Write Object name
else: # if EXPORT_GROUP_BY_OB:
file.write('g %s\n' % obnamestring)
# Vert
for v in me.verts:
file.write('v %.6f %.6f %.6f\n' % tuple(v.co))
# UV
if faceuv:
uv_face_mapping = [[0,0,0,0] for f in faces] # a bit of a waste for tri's :/
uv_dict = {} # could use a set() here
for f_index, f in enumerate(faces):
for uv_index, uv in enumerate(f.uv):
uvkey = veckey2d(uv)
try:
uv_face_mapping[f_index][uv_index] = uv_dict[uvkey]
except:
uv_face_mapping[f_index][uv_index] = uv_dict[uvkey] = len(uv_dict)
file.write('vt %.6f %.6f\n' % tuple(uv))
uv_unique_count = len(uv_dict)
del uv, uvkey, uv_dict, f_index, uv_index
# Only need uv_unique_count and uv_face_mapping
# NORMAL, Smooth/Non smoothed.
if EXPORT_NORMALS:
for f in faces:
if f.smooth:
for v in f:
noKey = veckey3d(v.no)
if not globalNormals.has_key( noKey ):
globalNormals[noKey] = totno
totno +=1
file.write('vn %.6f %.6f %.6f\n' % noKey)
else:
# Hard, 1 normal from the face.
noKey = veckey3d(f.no)
if not globalNormals.has_key( noKey ):
globalNormals[noKey] = totno
totno +=1
file.write('vn %.6f %.6f %.6f\n' % noKey)
if not faceuv:
f_image = None
for f_index, f in enumerate(faces):
f_v= f.v
f_smooth= f.smooth
f_mat = min(f.mat, len(materialNames)-1)
if faceuv:
f_image = f.image
f_uv= f.uv
# MAKE KEY
if faceuv and f_image: # Object is always true.
key = materialNames[f_mat], f_image.name
else:
key = materialNames[f_mat], None # No image, use None instead.
# CHECK FOR CONTEXT SWITCH
if key == contextMat:
pass # Context alredy switched, dont do anythoing
else:
if key[0] == None and key[1] == None:
# Write a null material, since we know the context has changed.
if EXPORT_GROUP_BY_MAT:
file.write('g %s_%s\n' % (fixName(ob.name), fixName(ob.getData(1))) ) # can be mat_image or (null)
file.write('usemtl (null)\n') # mat, image
else:
mat_data= MTL_DICT.get(key)
if not mat_data:
# First add to global dict so we can export to mtl
# Then write mtl
# Make a new names from the mat and image name,
# converting any spaces to underscores with fixName.
# If none image dont bother adding it to the name
if key[1] == None:
mat_data = MTL_DICT[key] = ('%s'%fixName(key[0])), materialItems[f_mat], f_image
else:
mat_data = MTL_DICT[key] = ('%s_%s' % (fixName(key[0]), fixName(key[1]))), materialItems[f_mat], f_image
if EXPORT_GROUP_BY_MAT:
file.write('g %s_%s_%s\n' % (fixName(ob.name), fixName(ob.getData(1)), mat_data[0]) ) # can be mat_image or (null)
file.write('usemtl %s\n' % mat_data[0]) # can be mat_image or (null)
contextMat = key
if f_smooth != contextSmooth:
if f_smooth: # on now off
file.write('s 1\n')
contextSmooth = f_smooth
else: # was off now on
file.write('s off\n')
contextSmooth = f_smooth
file.write('f')
if faceuv:
if EXPORT_NORMALS:
if f_smooth: # Smoothed, use vertex normals
for vi, v in enumerate(f_v):
file.write( ' %d/%d/%d' % (\
v.index+totverts,\
totuvco + uv_face_mapping[f_index][vi],\
globalNormals[ veckey3d(v.no) ])) # vert, uv, normal
else: # No smoothing, face normals
no = globalNormals[ veckey3d(f.no) ]
for vi, v in enumerate(f_v):
file.write( ' %d/%d/%d' % (\
v.index+totverts,\
totuvco + uv_face_mapping[f_index][vi],\
no)) # vert, uv, normal
else: # No Normals
for vi, v in enumerate(f_v):
#print _uv_face_mapping == tuple([tuple([0] * len(f)) for f in faces])
if len(uv_face_mapping) != len(faces):
raise "ass"
print f_index
print uv_face_mapping[f_index]
print vi
print uv_face_mapping[f_index][vi]
file.write( ' %d/%d' % (\
v.index+totverts,\
totuvco + uv_face_mapping[f_index][vi])) # vert, uv
face_vert_index += len(f_v)
else: # No UV's
if EXPORT_NORMALS:
if f_smooth: # Smoothed, use vertex normals
for v in f_v:
file.write( ' %d//%d' % (\
v.index+totverts,\
globalNormals[ veckey3d(v.no) ]))
else: # No smoothing, face normals
no = globalNormals[ veckey3d(f.no) ]
for v in f_v:
file.write( ' %d//%d' % (\
v.index+totverts,\
no))
else: # No Normals
for v in f_v:
file.write( ' %d' % (\
v.index+totverts))
file.write('\n')
# Write edges.
if EXPORT_EDGES:
LOOSE= Mesh.EdgeFlags.LOOSE
for ed in edges:
if ed.flag & LOOSE:
file.write('f %d %d\n' % (ed.v1.index+totverts, ed.v2.index+totverts))
# Make the indicies global rather then per mesh
totverts += len(me.verts)
if faceuv:
totuvco += uv_unique_count
me.verts= None
file.close()
# Now we have all our materials, save them
if EXPORT_MTL:
write_mtl(mtlfilename)
if EXPORT_COPY_IMAGES:
dest_dir = filename
# Remove chars until we are just the path.
while dest_dir and dest_dir[-1] not in '\\/':
dest_dir = dest_dir[:-1]
if dest_dir:
copy_images(dest_dir)
else:
print '\tError: "%s" could not be used as a base for an image path.' % filename
print "OBJ Export time: %.2f" % (sys.time() - time1)
def write_ui(filename):
if not filename.lower().endswith('.obj'):
filename += '.obj'
if not BPyMessages.Warning_SaveOver(filename):
return
EXPORT_APPLY_MODIFIERS = Draw.Create(1)
EXPORT_ROTX90 = Draw.Create(1)
EXPORT_TRI = Draw.Create(0)
EXPORT_EDGES = Draw.Create(1)
EXPORT_NORMALS = Draw.Create(0)
EXPORT_NORMALS_HQ = Draw.Create(1)
EXPORT_UV = Draw.Create(1)
EXPORT_MTL = Draw.Create(1)
EXPORT_SEL_ONLY = Draw.Create(1)
EXPORT_ALL_SCENES = Draw.Create(0)
EXPORT_ANIMATION = Draw.Create(0)
EXPORT_COPY_IMAGES = Draw.Create(0)
EXPORT_BLEN_OBS = Draw.Create(1)
EXPORT_GROUP_BY_OB = Draw.Create(0)
EXPORT_GROUP_BY_MAT = Draw.Create(0)
EXPORT_MORPH_TARGET = Draw.Create(0)
# removed too many options are bad!
# Get USER Options
pup_block = [\
('Context...'),\
('Selection Only', EXPORT_SEL_ONLY, 'Only export objects in visible selection. Else export whole scene.'),\
('All Scenes', EXPORT_ALL_SCENES, 'Each scene as a separate OBJ file.'),\
('Animation', EXPORT_ANIMATION, 'Each frame as a numbered OBJ file.'),\
('Object Prefs...'),\
('Apply Modifiers', EXPORT_APPLY_MODIFIERS, 'Use transformed mesh data from each object. May break vert order for morph targets.'),\
('Rotate X90', EXPORT_ROTX90 , 'Rotate on export so Blenders UP is translated into OBJs UP'),\
('Morph Target', EXPORT_MORPH_TARGET, 'Keep vert and face order, disables some other options.'),\
('Extra Data...'),\
('Edges', EXPORT_EDGES, 'Edges not connected to faces.'),\
('Normals', EXPORT_NORMALS, 'Export vertex normal data (Ignored on import).'),\
('High Quality Normals', EXPORT_NORMALS_HQ, 'Calculate high quality normals for rendering.'),\
('UVs', EXPORT_UV, 'Export texface UV coords.'),\
('Materials', EXPORT_MTL, 'Write a separate MTL file with the OBJ.'),\
('Copy Images', EXPORT_COPY_IMAGES, 'Copy image files to the export directory, never overwrite.'),\
('Triangulate', EXPORT_TRI, 'Triangulate quads.'),\
('Grouping...'),\
('Objects', EXPORT_BLEN_OBS, 'Export blender objects as "OBJ objects".'),\
('Object Groups', EXPORT_GROUP_BY_OB, 'Export blender objects as "OBJ Groups".'),\
('Material Groups', EXPORT_GROUP_BY_MAT, 'Group by materials.'),\
]
if not Draw.PupBlock('Export...', pup_block):
return
if EXPORT_MORPH_TARGET.val:
EXPORT_BLEN_OBS.val = False
EXPORT_GROUP_BY_OB.val = False
EXPORT_GROUP_BY_MAT.val = False
EXPORT_GROUP_BY_MAT.val = False
EXPORT_APPLY_MODIFIERS.val = False
Window.EditMode(0)
Window.WaitCursor(1)
EXPORT_APPLY_MODIFIERS = EXPORT_APPLY_MODIFIERS.val
EXPORT_ROTX90 = EXPORT_ROTX90.val
EXPORT_TRI = EXPORT_TRI.val
EXPORT_EDGES = EXPORT_EDGES.val
EXPORT_NORMALS = EXPORT_NORMALS.val
EXPORT_NORMALS_HQ = EXPORT_NORMALS_HQ.val
EXPORT_UV = EXPORT_UV.val
EXPORT_MTL = EXPORT_MTL.val
EXPORT_SEL_ONLY = EXPORT_SEL_ONLY.val
EXPORT_ALL_SCENES = EXPORT_ALL_SCENES.val
EXPORT_ANIMATION = EXPORT_ANIMATION.val
EXPORT_COPY_IMAGES = EXPORT_COPY_IMAGES.val
EXPORT_BLEN_OBS = EXPORT_BLEN_OBS.val
EXPORT_GROUP_BY_OB = EXPORT_GROUP_BY_OB.val
EXPORT_GROUP_BY_MAT = EXPORT_GROUP_BY_MAT.val
EXPORT_MORPH_TARGET = EXPORT_MORPH_TARGET.val
base_name, ext = splitExt(filename)
context_name = [base_name, '', '', ext] # basename, scene_name, framenumber, extension
# Use the options to export the data using write()
# def write(filename, objects, EXPORT_EDGES=False, EXPORT_NORMALS=False, EXPORT_MTL=True, EXPORT_COPY_IMAGES=False, EXPORT_APPLY_MODIFIERS=True):
orig_scene = Scene.GetCurrent()
if EXPORT_ALL_SCENES:
export_scenes = Scene.Get()
else:
export_scenes = [orig_scene]
# Export all scenes.
for scn in export_scenes:
scn.makeCurrent() # If alredy current, this is not slow.
context = scn.getRenderingContext()
orig_frame = Blender.Get('curframe')
if EXPORT_ALL_SCENES: # Add scene name into the context_name
context_name[1] = '_%s' % BPySys.cleanName(scn.name) # WARNING, its possible that this could cause a collision. we could fix if were feeling parranoied.
# Export an animation?
if EXPORT_ANIMATION:
scene_frames = xrange(context.startFrame(), context.endFrame()+1) # up to and including the end frame.
else:
scene_frames = [orig_frame] # Dont export an animation.
# Loop through all frames in the scene and export.
for frame in scene_frames:
if EXPORT_ANIMATION: # Add frame to the filename.
context_name[2] = '_%.6d' % frame
Blender.Set('curframe', frame)
if EXPORT_SEL_ONLY:
export_objects = scn.objects.context
else:
export_objects = scn.objects
full_path= ''.join(context_name)
# erm... bit of a problem here, this can overwrite files when exporting frames. not too bad.
# EXPORT THE FILE.
write(full_path, export_objects,\
EXPORT_TRI, EXPORT_EDGES, EXPORT_NORMALS,\
EXPORT_NORMALS_HQ, EXPORT_UV, EXPORT_MTL,\
EXPORT_COPY_IMAGES, EXPORT_APPLY_MODIFIERS,\
EXPORT_ROTX90, EXPORT_BLEN_OBS,\
EXPORT_GROUP_BY_OB, EXPORT_GROUP_BY_MAT, EXPORT_MORPH_TARGET)
Blender.Set('curframe', orig_frame)
# Restore old active scene.
orig_scene.makeCurrent()
Window.WaitCursor(0)
if __name__ == '__main__':
Window.FileSelector(write_ui, 'Export Wavefront OBJ', sys.makename(ext='.obj'))