export an armature to graphviz showing hierarchy, constraint and driver relationships, useful for understanding other peoples complicated rigs.

can be extended for 2.4x oops like graph too/

Example of Cessens spine rig
http://www.pasteall.org/pic/show.php?id=378

release/scripts/modules/graphviz_export.py

@@ -0,0 +1,119 @@
+# ##### 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 LICENSE BLOCK #####
+
+header = '''
+digraph ancestors           {
+graph [fontsize=30 labelloc="t" label="" splines=false overlap=true, rankdir=BT];
+ratio = "auto" ;
+'''
+
+footer = '''
+}
+'''
+
+def compat_str(text):
+    text = text.replace("\n", "\\n")
+    text = text.replace('"', '\\"')
+    return text
+
+def graph_armature(obj, path):
+    
+    file = open("/tmp/test.dot", "w")
+    fw = file.write
+    fw(header)
+    fw('label = "%s::%s" ;' % (bpy.data.filename.split("/")[-1].split("\\")[-1], obj.name))
+    
+    arm = obj.data
+    
+    for bone in arm.bones:
+        label = [bone.name]
+        for key, value in obj.pose.bones[bone.name].items():
+            if key.startswith("_"):
+                continue
+            
+            if type(value) == float:
+                value = "%.3f" % value
+            elif type(value) == str:
+                value = compat_str(value)
+            
+            label.append("%s = %s" % (key, value))
+        
+        opts = ["shape=box", "regular=1", "style=filled", "fillcolor=white", 'width="2.33"', 'height="0.35"', "fixedsize=false", 'label="%s"' % ("\\n".join(label))]
+        
+        fw('"%s" [%s];\n' % (bone.name, ','.join(opts)))
+    
+    for bone in arm.bones:
+        parent = bone.parent
+        if parent:
+            opts = ["dir=forward", "weight=2", "arrowhead=normal"]
+            if not bone.connected:
+                opts.append("style=dotted")
+            
+            fw('"%s" -> "%s" [%s] ;\n' % (bone.name, parent.name, ','.join(opts)))
+    del bone    
+    
+    # constraints
+    for pbone in obj.pose.bones:
+        for constraint in pbone.constraints:
+            subtarget = constraint.subtarget
+            if subtarget:
+                # TODO, not internal links
+                opts = ['dir=forward', "weight=1", "arrowhead=normal", "arrowtail=none", "constraint=false", 'color="red"'] # , 
+                label = "%s\n%s" % (constraint.type, constraint.name)
+                opts.append('label="%s"' % compat_str(label))
+                fw('"%s" -> "%s" [%s] ;\n' % (subtarget, pbone.name, ','.join(opts)))
+    
+    # Drivers
+    def rna_path_as_pbone(rna_path):
+        if not rna_path.startswith("pose.bones["):
+            return None
+
+        #rna_path_bone = rna_path[:rna_path.index("]") + 1]
+        #return obj.path_resolve(rna_path_bone)
+        bone_name = rna_path.split("[")[1].split("]")[0]
+        return obj.pose.bones[bone_name[1:-1]]
+    
+    for fcurve_driver in obj.animation_data.drivers:
+        rna_path = fcurve_driver.rna_path
+        pbone = rna_path_as_pbone(rna_path)
+            
+        if pbone:
+            for target in fcurve_driver.driver.targets:
+                pbone_target = rna_path_as_pbone(target.rna_path)
+                rna_path_target = target.rna_path
+                if pbone_target:
+                    opts = ['dir=forward', "weight=1", "arrowhead=normal", "arrowtail=none", "constraint=false", 'color="blue"'] # , 
+                    display_source = rna_path.replace("pose.bones", "")
+                    display_target = rna_path_target.replace("pose.bones", "")
+                    label = "%s\\n%s" % (display_source, display_target)
+                    opts.append('label="%s"' % compat_str(label))
+                    fw('"%s" -> "%s" [%s] ;\n' % (pbone_target.name, pbone.name, ','.join(opts)))
+    
+    fw(footer)
+    file.close()
+    
+    print(".", end='')
+    import sys
+    sys.stdout.flush()
+
+if __name__ == "__main__":
+    import bpy
+    import os
+    path ="/tmp/test.dot"
+    graph_armature(bpy.context.object, path)
+    os.system("dot -Tpng %s > %s; eog %s &" % (path, path + '.png', path + '.png'))