From 444e4e36feab32f86cda95c22e37b2d84ebee674 Mon Sep 17 00:00:00 2001
From: Campbell Barton <ideasman42@gmail.com>
Date: Tue, 2 May 2006 11:26:32 +0000
Subject: [PATCH] Commited 3ds export enhancements from Mark Stijnman
 (beowulff) Will need to do some updates, Mesh over NMesh and optimize some
 areas but it works and is a big improvement.

from
https://projects.blender.org/tracker/index.php?func=detail&aid=4156&group_id=9&atid=127

Detailed description:
Modified the 3ds export script 3ds_export.py:
- It now exports face UV correctly. 3ds only supports one UV coordinate per vertex. The script now duplicates vertices that had multiple UV pairs assigned to them so that each duplicate now only contains one and only one UV. Faces have their vertex indices adjusted accordingly.
- Quads are now split into triangles better. 3ds only supports triangles, so quads need to be split into two triangles. Instead of rather arbitrarily splitting along the diagonal between points 0 and 2, the script now splits along the shortest diagonal. This creates a higher quality triangular mesh, as well as better preservation of symmetry.
- Now creates an object node block, exporting object nodes, needed by some 3D importers. Among others, allows one to export object hierarchy.
- Now exports Empties as 3ds Dummies.

To be able to add all of the above new features, the script has been mostly rewritten and strongly restructured.

Motivation for the rewrite was the desire to be able to use Blender to produce custom 3d cars for Trackmania:Sunrise (TM:S). Previously, the TM:S importer could not correctly handle the 3ds files from the Blender 3ds export script. With this version, one can export cars complete with UV textures, correct wheel placement and light placement. To my knowledge, this script would make Blender the first fully free 3d modeller that allows one to export 3ds models for TM:S (expect a tutorial soon). The ability to have proper UV coordinates exported into the 3ds file should also be very welcome to many.

Add A Comment: Notepad
---
 release/scripts/3ds_export.py | 1276 +++++++++++++++++++--------------
 1 file changed, 736 insertions(+), 540 deletions(-)

diff --git a/release/scripts/3ds_export.py b/release/scripts/3ds_export.py
index ebe06c3d4eb..938afcd1bc6 100644
--- a/release/scripts/3ds_export.py
+++ b/release/scripts/3ds_export.py
@@ -2,21 +2,22 @@
 
 """ 
 Name: '3D Studio (.3ds)...'
-Blender: 237
+Blender: 241
 Group: 'Export'
 Tooltip: 'Export to 3DS file format (.3ds).'
 """
 
-__author__ = ["Campbell Barton", "Bob Holcomb", "Richard Lärkäng", "Damien McGinnes"]
-__url__ = ("blender", "elysiun", "http://www.gametutorials.com")
-__version__ = "0.82"
+__author__ = ["Campbell Barton", "Bob Holcomb", "Richard Lärkäng", "Damien McGinnes", "Mark Stijnman"]
+__url__ = ("blender", "elysiun", "http://www.gametutorials.com", "http://lib3ds.sourceforge.net/")
+__version__ = "0.90"
 __bpydoc__ = """\
 
 3ds Exporter
 
-This script Exports a 3ds file and the materials into blender for editing.
+This script Exports a 3ds file.
 
-Exporting is based on 3ds loader from www.gametutorials.com(Thanks DigiBen).
+Exporting is based on 3ds loader from www.gametutorials.com(Thanks DigiBen) and using information
+from the lib3ds project (http://lib3ds.sourceforge.net/) sourcecode.
 """
 
 # ***** BEGIN GPL LICENSE BLOCK *****
@@ -61,7 +62,7 @@ PRIMARY= long("0x4D4D",16)
 #------ Main Chunks
 OBJECTINFO   =      long("0x3D3D",16);      #This gives the version of the mesh and is found right before the material and object information
 VERSION      =      long("0x0002",16);      #This gives the version of the .3ds file
-EDITKEYFRAME=      long("0xB000",16);      #This is the header for all of the key frame info
+KFDATA       =      long("0xB000",16);      #This is the header for all of the key frame info
 
 #------ sub defines of OBJECTINFO
 MATERIAL=45055		#0xAFFF				// This stored the texture info
@@ -94,580 +95,775 @@ OBJECT_MATERIAL =   long("0x4130",16);      # This is found if the object has a
 OBJECT_UV       =   long("0x4140",16);      # The UV texture coordinates
 OBJECT_TRANS_MATRIX  =   long("0x4160",16); # The Object Matrix
 
+#>------ sub defines of KFDATA
+KFDATA_KFHDR            = long("0xB00A",16);
+KFDATA_KFSEG            = long("0xB008",16);
+KFDATA_KFCURTIME        = long("0xB009",16);
+KFDATA_OBJECT_NODE_TAG  = long("0xB002",16);
+
+#>------ sub defines of OBJECT_NODE_TAG
+OBJECT_NODE_ID          = long("0xB030",16);
+OBJECT_NODE_HDR         = long("0xB010",16);
+OBJECT_PIVOT            = long("0xB013",16);
+OBJECT_INSTANCE_NAME    = long("0xB011",16);
+POS_TRACK_TAG			= long("0xB020",16);
+ROT_TRACK_TAG			= long("0xB021",16);
+SCL_TRACK_TAG			= long("0xB022",16);
+
+
 #==============================================#
 # Strips the slashes from the back of a string #
 #==============================================#
 def stripPath(path):
+	"""Strips the slashes from the back of a string.
+	"""
 	return path.split('/')[-1].split('\\')[-1]
 
 #==================================================#
 # New name based on old with a different extension #
 #==================================================#
 def newFName(ext):
+	"""New name based on old with a different extension.
+	"""
 	return Blender.Get('filename')[: -len(Blender.Get('filename').split('.', -1)[-1]) ] + ext
 
 
-#the chunk class
-class chunk:
-	ID=0
+# size defines:	
+SZ_SHORT = 2
+SZ_INT   = 4
+SZ_FLOAT = 4
+
+class _3ds_short:
+	"""Class representing a short (2-byte integer) for a 3ds file."""
+	value=0
+	
+	def __init__(self, val=0):
+		self.value=val
+	
+	def get_size(self):
+		return SZ_SHORT
+
+	def write(self,file):
+		data=struct.pack("<H", self.value)
+		file.write(data)
+		
+	def __str__(self):
+		return str(self.value)
+
+class _3ds_int:
+	"""Class representing an int (4-byte integer) for a 3ds file."""
+	value=0
+	
+	def __init__(self, val=0):
+		self.value=val
+	
+	def get_size(self):
+		return SZ_INT
+
+	def write(self,file):
+		data=struct.pack("<I", self.value)
+		file.write(data)
+	
+	def __str__(self):
+		return str(self.value)
+
+class _3ds_float:
+	"""Class representing a 4-byte IEEE floating point number for a 3ds file."""
+	value=0.0
+	
+	def __init__(self, val=0.0):
+		self.value=val
+	
+	def get_size(self):
+		return SZ_FLOAT
+
+	def write(self,file):
+		data=struct.pack("<f", self.value)
+		file.write(data)
+		
+	
+	def __str__(self):
+		return str(self.value)
+
+
+class _3ds_string:
+	"""Class representing a zero-terminated string for a 3ds file."""
+	value=""
+	
+	def __init__(self, val=""):
+		self.value=val
+	
+	def get_size(self):
+		return (len(self.value)+1)
+
+	def write(self,file):
+		binary_format = "<%ds" % (len(self.value)+1)
+		data=struct.pack(binary_format, self.value)
+		file.write(data)
+		
+	
+	def __str__(self):
+		return self.value
+
+class _3ds_point_3d:
+	"""Class representing a three-dimensional point for a 3ds file."""
+	x=y=z=0.0
+	
+	def __init__(self, point=(0.0,0.0,0.0)):
+		self.x, self.y, self.z = point
+		
+	def get_size(self):
+		return 3*SZ_FLOAT
+
+	def write(self,file):
+		data=struct.pack("<3f", self.x, self.y, self.z)
+		file.write(data)
+	
+	def __str__(self):
+		return '(%f, %f, %f)' % (self.x, self.y, self.z)
+
+class _3ds_point_4d:
+	"""Class representing a four-dimensional point for a 3ds file, for instance a quaternion."""
+	x=y=z=w=0.0
+	
+	def __init__(self, point=(0.0,0.0,0.0,0.0)):
+		self.x, self.y, self.z, self.w = point	
+	
+	def get_size(self):
+		return 4*SZ_FLOAT
+
+	def write(self,file):
+		data=struct.pack("<4f", self.x, self.y, self.z, self.w)
+		file.write(data)
+
+	def __str__(self):
+		return '(%f, %f, %f, %f)' % (self.x, self.y, self.z, self.w)
+	
+class _3ds_point_uv:
+	"""Class representing a UV-coordinate for a 3ds file."""
+	uv=(0.0, 0.0)
+	
+	def __init__(self, point=(0.0,0.0)):
+		self.uv = point
+	
+	def __cmp__(self, other):
+		return cmp(self.uv,other.uv)	
+	
+	def get_size(self):
+		return 2*SZ_FLOAT
+	
+	def write(self,file):
+		data=struct.pack("<2f", self.uv[0], self.uv[1])
+		file.write(data)
+	
+	def __str__(self):
+		return '(%g, %g)' % self.uv
+
+class _3ds_rgb_color:
+	"""Class representing a (24-bit) rgb color for a 3ds file."""
+	r=g=b=0
+	
+	def __init__(self, col=(0,0,0)):
+		self.r, self.g, self.b = col
+	
+	def get_size(self):
+		return 3
+	
+	def write(self,file):
+		file.write( struct.pack("<c", chr(int(255*self.r))) )
+		file.write( struct.pack("<c", chr(int(255*self.g))) )
+		file.write( struct.pack("<c", chr(int(255*self.b))) )
+	
+	def __str__(self):
+		return '{%f, %f, %f}' % (self.r, self.g, self.b)
+
+class _3ds_face:
+	"""Class representing a face for a 3ds file."""
+
+	# vertex index tuple:
+	vindex=(0,0,0)
+	
+	def __init__(self, vindex):
+		self.vindex = vindex
+	
+	def get_size(self):
+		return 4*SZ_SHORT
+	
+	def write(self,file):
+		# The last zero is only used by 3d studio
+		data=struct.pack("<4H", self.vindex[0],self.vindex[1], self.vindex[2], 0) 
+		file.write(data)
+	
+	def __str__(self):
+		return '[%d %d %d]' % (self.vindex[0],self.vindex[1], self.vindex[2])
+
+class _3ds_array:
+	"""Class representing an array of variables for a 3ds file.
+
+	Consists of a _3ds_short to indicate the number of items, followed by the items themselves.
+	"""
+	values=[]
 	size=0
-
+	
 	def __init__(self):
-		self.ID=0
-		self.size=0
-
+		self.values=[]
+		self.size=SZ_SHORT
+	
+	# add an item:
+	def add(self,item):
+		self.values.append(item)
+		self.size+=item.get_size()
+	
 	def get_size(self):
-		self.size=6
-
-	def write(self, file):
-		#write header
-		data=struct.pack(\
-		"<HI",\
-		self.ID,\
-		self.size)
-		file.write(data)
-
-	def dump(self):
-		print "ID: ", self.ID
-		print "ID in hex: ", hex(self.ID)
-		print "size: ", self.size
-
-
-
-#may want to add light, camera, keyframe chunks.
-class vert_chunk(chunk):
-	verts=[]
-
-	def __init__(self):
-		self.verts=[]
-		self.ID=OBJECT_VERTICES
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=2 #for the number of verts short
-		temp_size += 12 * len(self.verts)  #3 floats x 4 bytes each
-		self.size+=temp_size
-		#~ print "vert_chunk size: ", self.size
 		return self.size
 	
-	def write(self, file):
-		chunk.write(self, file)
-		#write header
-		data=struct.pack("<H", len(self.verts))
-		file.write(data)
-		#write verts
-		for vert in self.verts:
-			data=struct.pack("<3f",vert[0],vert[1], vert[2])
-			file.write(data)
-
-class obj_material_chunk(chunk):
-	name=""
-	faces=[]
-
-	def __init__(self):
-		self.name=""
-		self.faces=[]
-		self.ID=OBJECT_MATERIAL
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=(len(self.name)+1)
-		temp_size+=2
-		for face in self.faces:
-			temp_size+=2
-		self.size+=temp_size
-		#~ print "obj material chunk size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write name
-		name_length=len(self.name)+1
-		binary_format="<"+str(name_length)+"s"
-		data=struct.pack(binary_format, self.name)
-		file.write(data)
-		binary_format="<H"
-		#~ print "Nr of faces: ", len(self.faces)
-		data=struct.pack(binary_format, len(self.faces))
-		file.write(data)
-		for face in self.faces:
-			data=struct.pack(binary_format, face)
-			file.write(data)
-
-class face_chunk(chunk):
-	faces=[]
-	num_faces=0
-	m_chunks=[]
-
-	def __init__(self):
-		self.faces=[]
-		self.ID=OBJECT_FACES
-		self.num_faces=0
-		self.m_chunks=[]
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size = 2 #num faces info
-		temp_size += 8 * len(self.faces)  #4 short ints x 2 bytes each
-		for m in self.m_chunks:
-			temp_size+=m.get_size()
-		self.size += temp_size
-		#~ print "face_chunk size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		data=struct.pack("<H", len(self.faces))
-		file.write(data)
-		#write faces
-		for face in self.faces:
-			data=struct.pack("<4H", face[0],face[1], face[2], 0) # The last zero is only used by 3d studio
-			file.write(data)
-		#write materials
-		for m in self.m_chunks:
-			m.write(file)
-
-class uv_chunk(chunk):
-	uv=[]
-	num_uv=0
-
-	def __init__(self):
-		self.uv=[]
-		self.ID=OBJECT_UV
-		self.num_uv=0
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=2 #for num UV
-		for this_uv in self.uv:
-			temp_size+=8  #2 floats at 4 bytes each
-		self.size+=temp_size
-		#~ print "uv chunk size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		
-		#write header
-		data=struct.pack("<H", len(self.uv))
-		file.write(data)
-		
-		#write verts
-		for this_uv in self.uv:
-			data=struct.pack("<2f", this_uv[0], this_uv[1])
-			file.write(data)
-
-class mesh_chunk(chunk):
-	v_chunk=vert_chunk()
-	f_chunk=face_chunk()
-	uv_chunk=uv_chunk()
-
-	def __init__(self):
-		self.v_chunk=vert_chunk()
-		self.f_chunk=face_chunk()
-		self.uv_chunk=uv_chunk()
-		self.ID=OBJECT_MESH
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=self.v_chunk.get_size()
-		temp_size+=self.f_chunk.get_size()
-		temp_size+=self.uv_chunk.get_size()
-		self.size+=temp_size
-		#~ print "object mesh chunk size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write stuff
-		self.v_chunk.write(file)
-		self.f_chunk.write(file)
-		self.uv_chunk.write(file)
-
-class object_chunk(chunk):
-	name=""
-	mesh_chunks=[]
-
-	def __init__(self):
-		self.name=""
-		self.mesh_chunks=[]
-		self.ID=OBJECT
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=len(self.name)+1 #+1 for null character
-		for mesh in self.mesh_chunks:
-			temp_size+=mesh.get_size()
-		self.size+=temp_size
-		#~ print "object chunk size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write name
-		
-		binary_format = "<%ds" % (len(self.name)+1)
-		data=struct.pack(binary_format, self.name)
-		file.write(data)
-		#write stuff
-		for mesh in self.mesh_chunks:
-			mesh.write(file)
-
-class object_info_chunk(chunk):
-	obj_chunks=[]
-	mat_chunks=[]
-
-	def __init__(self):
-		self.obj_chunks=[]
-		self.mat_chunks=[]
-		self.ID=OBJECTINFO
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=0
-		for mat in self.mat_chunks:
-			temp_size+=mat.get_size()
-		for obj in self.obj_chunks:
-			temp_size+=obj.get_size()
-		self.size+=temp_size
-		#~ print "object info size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write all the materials
-		for mat in self.mat_chunks:
-			mat.write(file)
-		#write all the objects
-		for obj in self.obj_chunks:
-			obj.write(file)
-
-
-
-class version_chunk(chunk):
-	version=3
-
-	def __init__(self):
-		self.ID=VERSION
-		self.version=3 #that the document that I'm using
-
-	def get_size(self):
-		chunk.get_size(self)
-		self.size += 4 #bytes for the version info
-		#~ print "version chunk size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write header and version
-		data=struct.pack("<I", self.version)
-		file.write(data)
-
-class rgb_chunk(chunk):
-	col=[]
-
-	def __init__(self):
-		self.col=[]
-
-	def get_size(self):
-		chunk.get_size(self)
-		self.size+=3 #color size
-		#~ print "rgb chunk size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write colors
-		for c in self.col:
-			file.write( struct.pack("<c", chr(int(255*c))) )
-
-
-class rgb1_chunk(rgb_chunk):
-
-	def __init__(self):
-		self.ID=RGB1
-
-class rgb2_chunk(rgb_chunk):
-
-	def __init__(self):
-		self.ID=RGB2
-
-class material_ambient_chunk(chunk):
-	col1=None
-	col2=None
-
-	def __init__(self):
-		self.ID=MATAMBIENT
-		self.col1=rgb1_chunk()
-		self.col2=rgb2_chunk()
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=self.col1.get_size()
-		temp_size+=self.col2.get_size()
-		self.size+=temp_size
-		#~ print "material ambient size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write colors
-		self.col1.write(file)
-		self.col2.write(file)
-
-class material_diffuse_chunk(chunk):
-	col1=None
-	col2=None
-
-	def __init__(self):
-		self.ID=MATDIFFUSE
-		self.col1=rgb1_chunk()
-		self.col2=rgb2_chunk()
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=self.col1.get_size()
-		temp_size+=self.col2.get_size()
-		self.size+=temp_size
-		#~ print "material diffuse size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write colors
-		self.col1.write(file)
-		self.col2.write(file)
-
-class material_specular_chunk(chunk):
-	col1=None
-	col2=None
-
-	def __init__(self):
-		self.ID=MATSPECULAR
-		self.col1=rgb1_chunk()
-		self.col2=rgb2_chunk()
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=self.col1.get_size()
-		temp_size+=self.col2.get_size()
-		self.size+=temp_size
-		#~ print "material specular size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write colors
-		self.col1.write(file)
-		self.col2.write(file)
-
-class material_name_chunk(chunk):
-	name=""
-
-	def __init__(self):
-		self.ID=MATNAME
-		self.name=""
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=(len(self.name)+1)
-		self.size+=temp_size
-		#~ print "material name size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write name
-		name_length=len(self.name)+1
-		binary_format="<"+str(name_length)+"s"
-		data=struct.pack(binary_format, self.name)
-		file.write(data)
-
-class material_chunk(chunk):
-	matname_chunk=None
-	matambient_chunk=None
-	matdiffuse_chunk=None
-	matspecular_chunk=None
-
-	def __init__(self):
-		self.ID=MATERIAL
-		self.matname_chunk=material_name_chunk()
-		self.matambient_chunk=material_ambient_chunk()
-		self.matdiffuse_chunk=material_diffuse_chunk()
-		self.matspecular_chunk=material_specular_chunk()
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=self.matname_chunk.get_size()
-		temp_size+=self.matambient_chunk.get_size()
-		temp_size+=self.matdiffuse_chunk.get_size()
-		temp_size+=self.matspecular_chunk.get_size()
-		self.size+=temp_size
-		#~ print "material chunk size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write name chunk
-		self.matname_chunk.write(file)
-		#write material colors
-		self.matambient_chunk.write(file)
-		self.matdiffuse_chunk.write(file)
-		self.matspecular_chunk.write(file)
-
-class primary_chunk(chunk):
-	version=None
-	obj_info=None
-
-	def __init__(self):
-		self.version=version_chunk()
-		self.obj_info=object_info_chunk()
-		self.ID=PRIMARY
-
-	def get_size(self):
-		chunk.get_size(self)
-		temp_size=self.version.get_size()
-		temp_size+=self.obj_info.get_size()
-		self.size+=temp_size
-		#~ print "primary chunk size: ", self.size
-		return self.size
-
-	def write(self, file):
-		chunk.write(self, file)
-		#write version chunk
-		self.version.write(file)
-		#write object_info chunk
-		self.obj_info.write(file)
-
-def read_chunk(file, chunk):
-		chunk.ID, chunk.size = \
-		struct.unpack(\
-		chunk.binary_format, \
-		file.read(struct.calcsize(chunk.binary_format))  )
+	def write(self,file):
+		_3ds_short(len(self.values)).write(file)
+		#_3ds_int(len(self.values)).write(file)
+		for value in self.values:
+			value.write(file)
 	
-def read_string(file):
-	s=""
-	index=0
+	# To not overwhelm the output in a dump, a _3ds_array only
+	# outputs the number of items, not all of the actual items. 
+	def __str__(self):
+		return '(%d items)' % len(self.values)
+
+class _3ds_named_variable:
+	"""Convenience class for named variables."""
 	
-	#read in the characters till we get a null character
-	data=struct.unpack("c", file.read(struct.calcsize("c")))
-	s=s+(data[0])
-	#print "string: ",s
-	while(ord(s[index])!=0):
-		index+=1
-		data=struct.unpack("c", file.read(struct.calcsize("c")))
-		s=s+(data[0])
-		#print "string: ",s
-	return str(s)
+	name=""
+	value=None
+	
+	def __init__(self, name, val=None):
+		self.name=name
+		self.value=val
+	
+	def get_size(self):
+		if (self.value==None): 
+			return 0
+		else:
+			return self.value.get_size()
+	
+	def write(self, file):
+		if (self.value!=None): 
+			self.value.write(file)
+	
+	def dump(self,indent):
+		if (self.value!=None):
+			spaces=""
+			for i in xrange(indent):
+				spaces+="  ";
+			if (self.name!=""):
+				print spaces, self.name, " = ", self.value
+			else:
+				print spaces, "[unnamed]", " = ", self.value
+
+
+#the chunk class
+class _3ds_chunk:
+	"""Class representing a chunk in a 3ds file.
+
+	Chunks contain zero or more variables, followed by zero or more subchunks.
+	"""
+
+	# The chunk ID:
+	ID=_3ds_short()
+	# The total chunk size (including the size of the chunk ID and chunk size!):
+	size=_3ds_int()
+	# Variables:
+	variables=[]
+	# Sub chunks:
+	subchunks=[]
+
+	def __init__(self, id=0):
+		self.ID=_3ds_short(id)
+		self.size=_3ds_int(0)
+		self.variables=[]
+		self.subchunks=[]
+	
+	def set_ID(id):
+		self.ID=_3ds_short(id)
+	
+	def add_variable(self, name, var):
+		"""Add a named variable. 
+		
+		The name is mostly for debugging purposes."""
+		self.variables.append(_3ds_named_variable(name,var))
+	
+	def add_subchunk(self, chunk):
+		"""Add a subchunk."""
+		self.subchunks.append(chunk)
+
+	def get_size(self):
+		"""Calculate the size of the chunk and return it.
+		
+		The sizes of the variables and subchunks are used to determine this chunk\'s size."""
+		tmpsize=self.ID.get_size()+self.size.get_size()
+		for variable in self.variables:
+			tmpsize+=variable.get_size()
+		for subchunk in self.subchunks:
+			tmpsize+=subchunk.get_size()
+		self.size.value=tmpsize
+		return self.size.value
+
+	def write(self, file):
+		"""Write the chunk to a file.
+		
+		Uses the write function of the variables and the subchunks to do the actual work."""
+		#write header
+		self.ID.write(file)
+		self.size.write(file)
+		for variable in self.variables:
+			variable.write(file)
+		for subchunk in self.subchunks:
+			subchunk.write(file)
+		
+		
+	def dump(self, indent=0):
+		"""Write the chunk to a file.
+		
+		Dump is used for debugging purposes, to dump the contents of a chunk to the standard output. 
+		Uses the dump function of the named variables and the subchunks to do the actual work."""
+		spaces=""
+		for i in xrange(indent):
+			spaces+="  ";
+		print spaces, "ID=", hex(self.ID.value), "size=", self.get_size()
+		for variable in self.variables:
+			variable.dump(indent+1)
+		for subchunk in self.subchunks:
+			subchunk.dump(indent+1)
+
+
 
 ######################################################
 # EXPORT
 ######################################################
+
+def make_material_subchunk(id, color):
+	"""Make a material subchunk.
+	
+	Used for color subchunks, such as diffuse color or ambient color subchunks."""
+	mat_sub = _3ds_chunk(id)
+	col1 = _3ds_chunk(RGB1)
+	col1.add_variable("color1", _3ds_rgb_color(color));
+	mat_sub.add_subchunk(col1)
+# optional:
+#	col2 = _3ds_chunk(RGB1)
+#	col2.add_variable("color2", _3ds_rgb_color(color));
+#	mat_sub.add_subchunk(col2)
+	return mat_sub
+
+
+def make_material_chunk(material):
+	"""Make a material chunk out of a blender material."""
+	material_chunk = _3ds_chunk(MATERIAL)
+	name = _3ds_chunk(MATNAME)
+	name.add_variable("name", _3ds_string(material.name))
+	material_chunk.add_subchunk(name)
+	ambCol = material.rgbCol
+	for i in xrange(len(ambCol)):
+		ambCol[i]*=material.amb;
+	material_chunk.add_subchunk(make_material_subchunk(MATAMBIENT, ambCol))
+	material_chunk.add_subchunk(make_material_subchunk(MATDIFFUSE, material.rgbCol))
+	material_chunk.add_subchunk(make_material_subchunk(MATSPECULAR, material.specCol))
+	return material_chunk
+
+class tri:
+	"""Class representing a triangle.
+	
+	Used when converting faces to triangles"""
+	
+	# vertex indices:
+	vertex_index=(0,0,0)
+	# material index:
+	mat_index=None
+	# uv coordinates (used on blender faces that have face-uv)
+	uvco=None
+	
+	def __init__(self, vindex=(0,0,0), mat=None, uvco=None):
+		self.vertex_index = vindex
+		self.mat = mat
+		self.uvco = uvco
+
+class UniqueList:
+	"""A list that only allows unique items.
+		
+	Trying to add an item that is not unique will give you the index where the item is already located."""
+	items=[]
+	
+	def __init__(self):
+		self.items=[]
+	
+	def add(self, new_item):
+		"""Add an item to the list and return the index at which it is added.
+		
+		If the item is already in the list, the index of the existing item is returned."""
+		found_index=None
+		for i,item in enumerate(self.items):
+			if (item==new_item):
+				found_index = i
+				break
+		if found_index==None:
+			found_index=len(self.items)
+			self.items.append(new_item)
+		return found_index
+
+
+def split_into_tri(face, do_uv=False):
+	"""Split a quad face into two triangles.
+		
+	The quad will be split along the shortest of its two diagonals."""
+	if (face[0].co-face[2].co).length < (face[1].co-face[3].co).length:
+		first_tri = tri((face[0].index, face[1].index, face[2].index), face.mat)
+		second_tri = tri((face[2].index, face[3].index, face[0].index), face.mat)
+		if (do_uv):
+			first_tri.uvco = (face.uv[0], face.uv[1], face.uv[2])
+			second_tri.uvco = (face.uv[2], face.uv[3], face.uv[0])
+	else:
+		first_tri = tri((face[0].index, face[1].index, face[3].index), face.mat)
+		second_tri = tri((face[1].index, face[2].index, face[3].index), face.mat)
+		if (do_uv):
+			first_tri.uvco = (face.uv[0], face.uv[1], face.uv[3])
+			second_tri.uvco = (face.uv[1], face.uv[2], face.uv[3])
+	return first_tri, second_tri
+	
+	
+def extract_triangles(mesh):
+	"""Extract triangles from a mesh.
+	
+	If the mesh contains quads, they will be split into triangles."""
+	tri_list = []
+	do_uv = mesh.hasFaceUV()
+	
+	for face in mesh.faces: 
+		if len(face) > 2:
+			num_fv = len(face)
+			if num_fv==3:
+				new_tri = tri((face[0].index, face[1].index, face[2].index), face.mat)
+				if (do_uv):
+					new_tri.uvco = face.uv
+				tri_list.append(new_tri)
+				
+			elif num_fv==4: #it's a quad
+				first_tri, second_tri = split_into_tri(face, do_uv)
+				tri_list.append(first_tri)
+				tri_list.append(second_tri)
+		
+	return tri_list
+	
+	
+def remove_face_uv(verts, tri_list):
+	"""Remove face UV coordinates from a list of triangles.
+		
+	Since 3ds files only support one pair of uv coordinates for each vertex, face uv coordinates
+	need to be converted to vertex uv coordinates. That means that vertices need to be duplicated when
+	there are multiple uv coordinates per vertex."""
+	
+	# initialize a list of UniqueLists, one per vertex:
+	uv_list = [UniqueList() for i in xrange(len(verts))]
+	
+	offset_list = [ ]
+	
+	# for each face uv coordinate, add it to the UniqueList of the vertex
+	for tri in tri_list:
+		offset = []
+		for i in xrange(3):
+			# store the index into the UniqueList for future reference:
+			offset.append(uv_list[tri.vertex_index[i]].add(_3ds_point_uv(tri.uvco[i])))
+		offset_list.append(offset)
+	# At this point, each vertex has a UniqueList containing every uv coordinate that is associated with it
+	# only once.
+	
+	# Now we need to duplicate every vertex as many times as it has uv coordinates and make sure the
+	# faces refer to the new face indices:
+	vert_index = 0
+	vert_array = _3ds_array()
+	uv_array = _3ds_array()
+	index_list=[]
+	for i,vert in enumerate(verts):
+		index_list.append(vert_index)
+		for uv in uv_list[i].items:
+			# add a vertex duplicate to the vertex_array for every uv associated with this vertex:
+			vert_array.add(_3ds_point_3d(vert))
+			# add the uv coordinate to the uv array:
+			uv_array.add(uv)
+			vert_index+=1
+	
+	# Make sure the triangle vertex indices now refer to the new vertex list:
+	for tri, offset in zip(tri_list, offset_list):
+		for i in xrange(3):
+			offset[i]+=index_list[tri.vertex_index[i]]
+		tri.vertex_index = offset
+	
+	return vert_array, uv_array, tri_list
+
+def make_faces_chunk(tri_list, materials):
+	"""Make a chunk for the faces.
+	
+	Also adds subchunks assigning materials to all faces."""
+	face_chunk = _3ds_chunk(OBJECT_FACES)
+	face_list = _3ds_array()
+	
+	obj_material_faces=[]
+	obj_material_names=[]
+	for m in materials:
+		obj_material_names.append(_3ds_string(m.name))
+		obj_material_faces.append(_3ds_array())
+	n_materials = len(obj_material_names)
+	
+	for i,tri in enumerate(tri_list):
+		face_list.add(_3ds_face(tri.vertex_index))
+		if (tri.mat < n_materials):
+			obj_material_faces[tri.mat].add(_3ds_short(i))
+	
+	face_chunk.add_variable("faces", face_list)
+
+	for i in xrange(n_materials):
+		obj_material_chunk=_3ds_chunk(OBJECT_MATERIAL)
+		obj_material_chunk.add_variable("name", obj_material_names[i])
+		obj_material_chunk.add_variable("face_list", obj_material_faces[i])
+		face_chunk.add_subchunk(obj_material_chunk)
+
+	return face_chunk
+
+def make_vert_chunk(vert_array):
+	"""Make a vertex chunk out of an array of vertices."""
+	vert_chunk = _3ds_chunk(OBJECT_VERTICES)
+	vert_chunk.add_variable("vertices",vert_array)
+	return vert_chunk
+
+def make_uv_chunk(uv_array):
+	"""Make a UV chunk out of an array of UVs."""
+	uv_chunk = _3ds_chunk(OBJECT_UV)
+	uv_chunk.add_variable("uv coords", uv_array)
+	return uv_chunk
+
+def make_mesh_chunk(mesh):
+	"""Make a chunk out of a Blender mesh."""
+	
+	# Extract the triangles from the mesh:
+	tri_list = extract_triangles(mesh)
+	
+	if (mesh.hasFaceUV()):
+		# Remove the face UVs and convert it to vertex UV:
+		vert_array, uv_array, tri_list = remove_face_uv(mesh.verts, tri_list)
+	else:
+		# Add the vertices to the vertex array:
+		vert_array = _3ds_array()
+		for vert in mesh.verts:
+			vert_array.add(_3ds_point_3d(vert.co))
+		# If the mesh has vertex UVs, create an array of UVs:
+		if (mesh.hasVertexUV()):
+			uv_array = _3ds_array()
+			for vert in mesh.verts:
+				uv_array.add(_3ds_point_uv(vert.uvco))
+		else:
+			# no UV at all:
+			uv_array = None
+
+	# create the chunk:
+	mesh_chunk = _3ds_chunk(OBJECT_MESH)
+	
+	# add vertex chunk:
+	mesh_chunk.add_subchunk(make_vert_chunk(vert_array))
+	# add faces chunk:
+	mesh_chunk.add_subchunk(make_faces_chunk(tri_list, mesh.materials))
+	# if available, add uv chunk:
+	if uv_array:
+		mesh_chunk.add_subchunk(make_uv_chunk(uv_array))
+	
+	return mesh_chunk
+
+def make_kfdata(start=0, stop=0, curtime=0):
+	"""Make the basic keyframe data chunk"""
+	kfdata = _3ds_chunk(KFDATA)
+	
+	kfhdr = _3ds_chunk(KFDATA_KFHDR)
+	kfhdr.add_variable("revision", _3ds_short(0))
+	# Not really sure what filename is used for, but it seems it is usually used
+	# to identify the program that generated the .3ds:
+	kfhdr.add_variable("filename", _3ds_string("Blender"))
+	kfhdr.add_variable("animlen", _3ds_int(stop-start))
+	
+	kfseg = _3ds_chunk(KFDATA_KFSEG)
+	kfseg.add_variable("start", _3ds_int(start))
+	kfseg.add_variable("stop", _3ds_int(stop))
+	
+	kfcurtime = _3ds_chunk(KFDATA_KFCURTIME)
+	kfcurtime.add_variable("curtime", _3ds_int(curtime))
+	
+	kfdata.add_subchunk(kfhdr)
+	kfdata.add_subchunk(kfseg)
+	kfdata.add_subchunk(kfcurtime)
+	return kfdata
+
+def make_track_chunk(ID, obj):
+	"""Make a chunk for track data.
+	
+	Depending on the ID, this will construct a position, rotation or scale track."""
+	track_chunk = _3ds_chunk(ID)
+	track_chunk.add_variable("track_flags", _3ds_short())
+	track_chunk.add_variable("unknown", _3ds_int())
+	track_chunk.add_variable("unknown", _3ds_int())
+	track_chunk.add_variable("nkeys", _3ds_int(1))
+	# Next section should be repeated for every keyframe, but for now, animation is not actually supported.
+	track_chunk.add_variable("tcb_frame", _3ds_int(0))
+	track_chunk.add_variable("tcb_flags", _3ds_short())
+	if ID==POS_TRACK_TAG:
+		# position vector:
+		track_chunk.add_variable("position", _3ds_point_3d(obj.getLocation()))
+	elif ID==ROT_TRACK_TAG:
+		# rotation (quaternion, angle first, followed by axis):
+		q = obj.getEuler().toQuat()
+		track_chunk.add_variable("rotation", _3ds_point_4d((q.angle, q.axis[0], q.axis[1], q.axis[2])))
+	elif ID==SCL_TRACK_TAG:
+		# scale vector:
+		track_chunk.add_variable("scale", _3ds_point_3d(obj.getSize()))
+	
+	return track_chunk
+
+def make_kf_obj_node(obj, name_to_id):
+	"""Make a node chunk for a Blender object.
+	
+	Takes the Blender object as a parameter. Object id's are taken from the dictionary name_to_id.
+	Blender Empty objects are converted to dummy nodes."""
+	
+	name = obj.getName()
+	# main object node chunk:
+	kf_obj_node = _3ds_chunk(KFDATA_OBJECT_NODE_TAG)
+	# chunk for the object id: 
+	obj_id_chunk = _3ds_chunk(OBJECT_NODE_ID)
+	# object id is from the name_to_id dictionary:
+	obj_id_chunk.add_variable("node_id", _3ds_short(name_to_id[name]))
+	
+	# object node header:
+	obj_node_header_chunk = _3ds_chunk(OBJECT_NODE_HDR)
+	# object name:
+	if (obj.getType() == 'Empty'):
+		# Empties are called "$$$DUMMY" and use the OBJECT_INSTANCE_NAME chunk 
+		# for their name (see below):
+		obj_node_header_chunk.add_variable("name", _3ds_string("$$$DUMMY"))
+	else:
+		# Add the name:
+		obj_node_header_chunk.add_variable("name", _3ds_string(name))
+	# Add Flag variables (not sure what they do):
+	obj_node_header_chunk.add_variable("flags1", _3ds_short(0))
+	obj_node_header_chunk.add_variable("flags2", _3ds_short(0))
+	
+	# Check parent-child relationships:
+	parent = obj.getParent()
+	if (parent == None) or (parent.getName() not in name_to_id):
+		# If no parent, or the parents name is not in the name_to_id dictionary,
+		# parent id becomes -1:
+		obj_node_header_chunk.add_variable("parent", _3ds_short(-1))
+	else:
+		# Get the parent's id from the name_to_id dictionary:
+		obj_node_header_chunk.add_variable("parent", _3ds_short(name_to_id[parent.getName()]))
+	
+	# Add pivot chunk:
+	obj_pivot_chunk = _3ds_chunk(OBJECT_PIVOT)
+	obj_pivot_chunk.add_variable("pivot", _3ds_point_3d(obj.getLocation()))
+	kf_obj_node.add_subchunk(obj_pivot_chunk)
+	
+	# add subchunks for object id and node header:
+	kf_obj_node.add_subchunk(obj_id_chunk)
+	kf_obj_node.add_subchunk(obj_node_header_chunk)
+
+	# Empty objects need to have an extra chunk for the instance name:
+	if (obj.getType() == 'Empty'):
+		obj_instance_name_chunk = _3ds_chunk(OBJECT_INSTANCE_NAME)
+		obj_instance_name_chunk.add_variable("name", _3ds_string(name))
+		kf_obj_node.add_subchunk(obj_instance_name_chunk)
+	
+	# Add track chunks for position, rotation and scale:
+	kf_obj_node.add_subchunk(make_track_chunk(POS_TRACK_TAG, obj))
+	kf_obj_node.add_subchunk(make_track_chunk(ROT_TRACK_TAG, obj))
+	kf_obj_node.add_subchunk(make_track_chunk(SCL_TRACK_TAG, obj))
+
+	return kf_obj_node
+
+
 def save_3ds(filename):
+	"""Save the Blender scene to a 3ds file."""
 	# Time the export
 	time1 = Blender.sys.time()
 
-	exported_materials = {}
-
-	#fill the chunks full of data
-	primary=primary_chunk()
-	#get all the objects in this scene
-	object_list = [ ob for ob in Blender.Object.GetSelected() if ob.getType() == 'Mesh' ]
-	#fill up the data structures with objects
-	for obj in object_list:
+	# Initialize the main chunk (primary):
+	primary = _3ds_chunk(PRIMARY)
+	# Add version chunk:
+	version_chunk = _3ds_chunk(VERSION)
+	version_chunk.add_variable("version", _3ds_int(3))
+	primary.add_subchunk(version_chunk)
+	
+	# init main object info chunk:
+	object_info = _3ds_chunk(OBJECTINFO)
+	
+	# init main key frame data chunk:
+	kfdata = make_kfdata()
+	
+	# Make chunks for all materials in the scene:
+	for material in Material.Get():
+		object_info.add_subchunk(make_material_chunk(material))
+	
+	
+	# Get all the supported objects in this scene
+	mesh_objects = [ ob for ob in Blender.Object.Get() if ob.getType() == 'Mesh' ]
+	empty_objects = [ ob for ob in Blender.Object.Get() if ob.getType() == 'Empty' ]
+	
+	all_objects = mesh_objects + empty_objects
+	
+	# Give all objects a unique ID and build a dictionary from object name to object id:
+	name_to_id = {}
+	for i,obj in enumerate(all_objects):
+		name_to_id[obj.getName()] = i
+	
+	# Create object chunks for all meshes:
+	for obj in mesh_objects:
 		#create a new object chunk
-		primary.obj_info.obj_chunks.append(object_chunk())
+		object_chunk = _3ds_chunk(OBJECT)
+		
 		#get the mesh data
 		blender_mesh = obj.getData()
 		blender_mesh.transform(obj.getMatrix())
+		
 		#set the object name
-		primary.obj_info.obj_chunks[len(primary.obj_info.obj_chunks)-1].name=obj.getName()
-
-		matrix = obj.getMatrix()
-
-		#make a new mesh chunk object
-		mesh=mesh_chunk()
+		object_chunk.add_variable("name", _3ds_string(obj.getName()))
 		
-		mesh.v_chunk.verts = blender_mesh.verts
+		# make a mesh chunk out of the mesh:
+		object_chunk.add_subchunk(make_mesh_chunk(blender_mesh))
+		object_info.add_subchunk(object_chunk)
 		
-		dummy = None # just incase...
-		
-		for m in blender_mesh.materials:
-			mesh.f_chunk.m_chunks.append(obj_material_chunk())
-			mesh.f_chunk.m_chunks[len(mesh.f_chunk.m_chunks)-1].name = m.name
+		# make a kf object node for the object:
+		kfdata.add_subchunk(make_kf_obj_node(obj, name_to_id))
 
-			# materials should only be exported once
-			try:
-				dummy = exported_materials[m.name]
-				
-				
-			except KeyError:
-				material = material_chunk()
-				material.matname_chunk.name=m.name
-				material.matambient_chunk.col1.col = m.mirCol
-				material.matambient_chunk.col2.col = m.mirCol
-				material.matdiffuse_chunk.col1.col = m.rgbCol
-				material.matdiffuse_chunk.col2.col = m.rgbCol
-				material.matspecular_chunk.col1.col = m.specCol
-				material.matspecular_chunk.col2.col = m.specCol
-				
-				primary.obj_info.mat_chunks.append(material)
-				
-				exported_materials[m.name] = None
-		
-		del dummy # unpolute the namespace
-		
-		valid_faces = [f for f in blender_mesh.faces if len(f) > 2]
-		facenr=0
-		#fill in faces
-		for face in valid_faces:
-			
-			#is this a tri or a quad
-			num_fv=len(face.v)
-			
-			
-			#it's a tri
-			if num_fv==3:
-				mesh.f_chunk.faces.append((face[0].index, face[1].index, face[2].index))
-				if (face.materialIndex < len(mesh.f_chunk.m_chunks)):
-					mesh.f_chunk.m_chunks[face.materialIndex].faces.append(facenr)
-				facenr+=1
-			
-			else: #it's a quad					
-				mesh.f_chunk.faces.append((face[0].index, face[1].index, face[2].index))  # 0,1,2
-				mesh.f_chunk.faces.append((face[2].index, face[3].index, face[0].index))  # 2,3,0
-				#first tri
-				if (face.materialIndex < len(mesh.f_chunk.m_chunks)):
-					mesh.f_chunk.m_chunks[face.materialIndex].faces.append(facenr)
-				facenr+=1
-				#other tri
-				if (face.materialIndex < len(mesh.f_chunk.m_chunks)):
-					mesh.f_chunk.m_chunks[face.materialIndex].faces.append(facenr)
-				facenr+=1
-			
-
-		#fill in the UV info
-		if blender_mesh.hasVertexUV():
-			for vert in blender_mesh.verts:
-				mesh.uv_chunk.uv.append((vert.uvco[0], vert.uvco[1]))
-
-		elif blender_mesh.hasFaceUV():
-			for face in valid_faces:
-				# Tri or quad.
-				for uv_coord in face.uv:
-					mesh.uv_chunk.uv.append((uv_coord[0], uv_coord[1]))
-
-		#filled in our mesh, lets add it to the file
-		primary.obj_info.obj_chunks[len(primary.obj_info.obj_chunks)-1].mesh_chunks.append(mesh)
-
-	#check the size
+	# Create chunks for all empties:
+	for obj in empty_objects:
+		# Empties only require a kf object node:
+		kfdata.add_subchunk(make_kf_obj_node(obj, name_to_id))
+	
+	# Add main object info chunk to primary chunk:
+	primary.add_subchunk(object_info)
+	# Add main keyframe data chunk to primary chunk:
+	primary.add_subchunk(kfdata)
+	
+	# At this point, the chunk hierarchy is completely built.
+	
+	# Check the size:
 	primary.get_size()
-	#open the files up for writing
+	# Open the file for writing:
 	file = open( filename, "wb" )
-	#recursively write the stuff to file
+	
+	# Recursively write the chunks to file:
 	primary.write(file)
+	
+	# Close the file:
 	file.close()
+	
+	# Debugging only: report the exporting time:
 	print "3ds export time: %.2f" % (Blender.sys.time() - time1)
 	
+	# Debugging only: dump the chunk hierarchy:
+	#primary.dump()
+	
 
 Blender.Window.FileSelector(save_3ds, "Export 3DS", newFName('3ds'))