diff --git a/main/Scene.cc b/main/Scene.cc
index bd97bd8..deb3690 100644
--- a/main/Scene.cc
+++ b/main/Scene.cc
@@ -60,6 +60,10 @@ Scene::Scene(const map<string, const char *> & options,
         {
             m_max_depth = atoi(it->second);
         }
+        else if (it->first == "ambient-occlusion")
+        {
+            m_ambient_occlusion_level = atoi(it->second);
+        }
     }
 
     /* view plane distance is calculated based on the field of view */
diff --git a/main/Scene.h b/main/Scene.h
index eccfa08..231b2d2 100644
--- a/main/Scene.h
+++ b/main/Scene.h
@@ -35,11 +35,13 @@ class Scene
         void setVFOV(double vfov) { m_vfov = vfov; }
         void setAmbientLight(const Color & al) { m_ambient_light = al; }
         void renderPixel(int x, int y, unsigned char * pixel);
+        void setMaxDepth(int d) { m_max_depth = d; }
         int getWidth() { return m_width; }
         int getHeight() { return m_height; }
         int getMultisampleLevel() { return m_multisample_level; }
         int getAmbientOcclusionLevel() { return m_ambient_occlusion_level; }
         double getVFOV() { return m_vfov; }
+        int getMaxDepth() { return m_max_depth; }
 
     protected:
         /* private methods */
diff --git a/main/fart.cc b/main/fart.cc
index 386c2ab..0030d8e 100644
--- a/main/fart.cc
+++ b/main/fart.cc
@@ -26,6 +26,8 @@ void usage(const char * progname)
     cout << "    -m|--multisample <level>" << endl;
     cout << "    -f|--field-of-view <vertical-fov>" << endl;
     cout << "    -d|--max-depth <max-recursion-depth>" << endl;
+    cout << "    -a|--ambient-occlusion <ambient-occlusion-level>" << endl;
+    cout << "    -p|--preview  (means -w400 -h300 -m1 -d8 -a0)" << endl;
     cout << "       --hosts <hosts-file>" << endl;
     exit(42);
 }
@@ -90,25 +92,32 @@ int main(int argc, char * argv[])
     bool child = false;
 
     static const struct option long_options[] = {
-        { "output-file",    required_argument, NULL, 'o' },
-        { "width",          required_argument, NULL, 'w' },
-        { "height",         required_argument, NULL, 'h' },
-        { "multisample",    required_argument, NULL, 'm' },
-        { "field-of-view",  required_argument, NULL, 'f' },
-        { "max-depth",      required_argument, NULL, 'd' },
-        { "help",           no_argument,       NULL, 256 },
-        { "host",           required_argument, NULL, 257 },
-        { "port",           required_argument, NULL, 258 },
-        { "hosts",          required_argument, NULL, 259 },
-        { "child",          no_argument,       NULL, 260 },
-        { NULL,             0,                 NULL, 0   }
+        { "ambient-occlusion",  required_argument, NULL, 'a' },
+        { "output-file",        required_argument, NULL, 'o' },
+        { "width",              required_argument, NULL, 'w' },
+        { "height",             required_argument, NULL, 'h' },
+        { "multisample",        required_argument, NULL, 'm' },
+        { "field-of-view",      required_argument, NULL, 'f' },
+        { "max-depth",          required_argument, NULL, 'd' },
+        { "preview",            no_argument,       NULL, 'p' },
+        { "help",               no_argument,       NULL, 256 },
+        { "host",               required_argument, NULL, 257 },
+        { "port",               required_argument, NULL, 258 },
+        { "hosts",              required_argument, NULL, 259 },
+        { "child",              no_argument,       NULL, 260 },
+        { NULL,                 0,                 NULL, 0   }
     };
 
-    while ((opt = getopt_long(argc, argv, "o:w:h:m:f:d:",
+    while ((opt = getopt_long(argc, argv, "a:o:w:h:m:f:d:p",
                               long_options, &option_index)) != -1)
     {
         switch (opt)
         {
+            case 'a':
+                scene_options["ambient-occlusion"] = optarg;
+                client_options.push_back("--ambient-occlusion");
+                client_options.push_back(optarg);
+                break;
             case 'o':
                 output_file_name = optarg;
                 break;
@@ -137,6 +146,14 @@ int main(int argc, char * argv[])
                 client_options.push_back("--max-depth");
                 client_options.push_back(optarg);
                 break;
+            case 'p':
+                scene_options["ambient-occlusion"] = "0";
+                scene_options["width"] = "400";
+                scene_options["height"] = "300";
+                scene_options["multisample"] = "1";
+                scene_options["max-depth"] = "8";
+                client_options.push_back("--preview");
+                break;
             case 256:
                 usage(argv[0]);
                 break;
@@ -189,6 +206,7 @@ int main(int argc, char * argv[])
         cout << "    Multisample Level: " << scene.getMultisampleLevel() << endl;
         cout << "    Ambient Occlusion Level: " << scene.getAmbientOcclusionLevel() << endl;
         cout << "    Vertical Field of View: " << scene.getVFOV() << endl;
+        cout << "    Max Depth: " << scene.getMaxDepth() << endl;
         cout << "----------------------------------------" << endl;
     }