diff --git a/vapory/config.py b/vapory/config.py
index 4a45def..ff720ce 100644
--- a/vapory/config.py
+++ b/vapory/config.py
@@ -1,6 +1,8 @@
 import os
 
-POVRAY_BINARY = ("povray.exe" if os.name=='nt' else "povray")
+POVRAY_BINARY = os.environ.get('POVRAY_BINARY') or (
+    "povray.exe" if os.name == 'nt' else "povray"
+)
 
 GLOBAL_SCENE_SETTINGS = {
     "charset"        : "ascii",
diff --git a/vapory/io.py b/vapory/io.py
index 62f6c27..f86c0ee 100644
--- a/vapory/io.py
+++ b/vapory/io.py
@@ -54,7 +54,8 @@ def ppm_to_numpy(filename=None, buffer=None, byteorder='>'):
 
 def render_povstring(string, outfile=None, height=None, width=None,
                      quality=None, antialiasing=None, remove_temp=True,
-                     show_window=False, tempfile=None, includedirs=None):
+                     show_window=False, tempfile=None, includedirs=None,
+                     alpha=None, additional_args=None):
 
     """ Renders the provided scene description with POV-Ray.
 
@@ -108,6 +109,10 @@ def render_povstring(string, outfile=None, height=None, width=None,
             cmd.append('+L%s'%dir)
     cmd.append("Output_File_Type=%s"%format_type)
     cmd.append("+O%s"%outfile)
+    if alpha:
+        cmd.append("Output_Alpha=on")
+
+    cmd += additional_args or []
     process = subprocess.Popen(cmd, stderr=subprocess.PIPE,
                                     stdin=subprocess.PIPE,
                                     stdout=subprocess.PIPE)
diff --git a/vapory/vapory.py b/vapory/vapory.py
index 99f99eb..6f60955 100644
--- a/vapory/vapory.py
+++ b/vapory/vapory.py
@@ -1,5 +1,6 @@
 import webbrowser # <= to open the POVRay help
 from copy import deepcopy
+from itertools import chain
 import re
 from .io import render_povstring
 
@@ -37,7 +38,7 @@ def __str__(self):
         global_settings = ["global_settings{\n%s\n}"%("\n".join(
                            [str(e) for e in self.global_settings]))]
         return '\n'.join([str(e)
-                          for l in  [included, declares, self.objects, [self.camera],
+                          for l in  [included, declares, defaults, self.objects, [self.camera],
                               self.atmospheric, global_settings]
                           for e in l])
 
@@ -50,15 +51,14 @@ def set_camera(self, new_camera):
         return new
 
     def add_objects(self, objs):
-
         new = self.copy()
-        new.objects +=  objs
+        new.objects += objs
         return new
 
     def render(self, outfile=None, height=None, width=None,
                      quality=None, antialiasing=None, remove_temp=True,
                      auto_camera_angle=True, show_window=False, tempfile=None,
-                     includedirs=None):
+                     includedirs=None, alpha=None, additional_args=None):
 
         """ Renders the scene to a PNG, a numpy array, or the IPython Notebook.
 
@@ -84,12 +84,17 @@ def render(self, outfile=None, height=None, width=None,
 
         return render_povstring(str(self), outfile, height, width,
                                 quality, antialiasing, remove_temp, show_window,
-                                tempfile, includedirs)
+                                tempfile, includedirs,
+                                alpha=alpha,
+                                additional_args=additional_args)
 
 
 class POVRayElement:
-    def __init__(self, *args):
-        self.args = list(args)
+    def __init__(self, *args, **kwargs):
+        args = list(args)
+        # flat key arguments - Obj(value='x') -> Obj('value', 'x')
+        args += list(chain.from_iterable(kwargs.items()))
+        self.args = args
 
     def copy(self):
         return deepcopy(self)
diff --git a/vapory/version.py b/vapory/version.py
index faa7b74..ff4ba4c 100644
--- a/vapory/version.py
+++ b/vapory/version.py
@@ -1 +1 @@
-__version__ = "0.1.01"
+__version__ = "0.1.02"