diff --git a/Polyhedron/demo/Polyhedron/resources/shader_c3t3.frag b/Polyhedron/demo/Polyhedron/resources/shader_c3t3.frag
index 27b255c5e1c..9408f3d5932 100644
--- a/Polyhedron/demo/Polyhedron/resources/shader_c3t3.frag
+++ b/Polyhedron/demo/Polyhedron/resources/shader_c3t3.frag
@@ -2,6 +2,7 @@
 in vec4 color;
 in vec4 fP; 
 in vec3 fN; 
+in float dist[6];
 flat in vec2 subdomain_out;
 uniform vec4 light_pos;  
 uniform vec4 light_diff; 
@@ -10,6 +11,7 @@ uniform vec4 light_amb;
 uniform float spec_power ;
 uniform int is_two_side; 
 uniform bool is_selected;
+uniform bool is_clipbox_on;
 uniform float near;
 uniform float far;
 uniform float width;
@@ -28,7 +30,19 @@ float depth(float z)
   return (2 * near) / (far + near - z * (far - near));
 }
 
-void main(void) {
+bool compute_clip_visibility() {
+  if(is_clipbox_on)
+    return dist[0]>0.0 ||
+      dist[1]>0.0 ||
+      dist[2]>0.0 ||
+      dist[3]>0.0 ||
+      dist[4]>0.0 ||
+      dist[5]>0.0;
+  else
+    return false;
+}
+
+bool compute_filtering_visibility() {
   if(is_filterable)
   {
     uint domain1 = uint(subdomain_out.x);
@@ -37,10 +51,15 @@ void main(void) {
     uint i2 = domain2/25u;
     uint visible1 = uint(is_visible_bitset[i1]);
     uint visible2 = uint(is_visible_bitset[i2]);
-    if((visible1>>(domain1%25u))%2u == 0u && (visible2>>(domain2%25u))%2u == 0u)
-    {
-      discard;
-    }
+    return (visible1>>(domain1%25u))%2u == 0u && (visible2>>(domain2%25u))%2u == 0u;
+  }
+  else
+    return false;
+}
+
+void main(void) {
+  if (compute_clip_visibility() || compute_filtering_visibility()) {
+    discard;
   }
   float d = depth(gl_FragCoord.z);
   float test = texture(sampler, vec2(gl_FragCoord.x/width, gl_FragCoord.y/height)).r;
diff --git a/Polyhedron/demo/Polyhedron/resources/shader_c3t3.vert b/Polyhedron/demo/Polyhedron/resources/shader_c3t3.vert
index 2298a14b15c..b7677129d66 100644
--- a/Polyhedron/demo/Polyhedron/resources/shader_c3t3.vert
+++ b/Polyhedron/demo/Polyhedron/resources/shader_c3t3.vert
@@ -12,13 +12,37 @@ uniform  float shrink_factor;
 out vec4 fP;
 out vec3 fN;
 out vec4 color;
+out float dist[6];
 flat out vec2 subdomain_out;
+uniform bool is_clipbox_on;
+uniform mat4 clipbox1;
+uniform mat4 clipbox2;
 uniform  float point_size;
+
+void compute_distances(void)
+{
+  for(int i=0; i<3; ++i)
+  {
+    dist[i]=
+    clipbox1[i][0]*vertex.x+
+    clipbox1[i][1]*vertex.y+
+    clipbox1[i][2]*vertex.z +
+    clipbox1[i][3];
+    dist[i+3]=
+    clipbox2[i][0]*vertex.x+
+    clipbox2[i][1]*vertex.y+
+    clipbox2[i][2]*vertex.z +
+    clipbox2[i][3];
+  }
+}
+
 void main(void)
 {
   subdomain_out = subdomain_in;
   gl_PointSize = point_size;
   color = vec4(colors, vertex.x * cutplane.x  + vertex.y * cutplane.y  + vertex.z * cutplane.z  +  cutplane.w);
+  if(is_clipbox_on)
+   compute_distances();
   fP = mv_matrix * vertex;
 
   mat3 norm_matrix_3;
diff --git a/Polyhedron/demo/Polyhedron/resources/shader_c3t3_edges.frag b/Polyhedron/demo/Polyhedron/resources/shader_c3t3_edges.frag
index c3fbb6bba00..d15d6e12512 100644
--- a/Polyhedron/demo/Polyhedron/resources/shader_c3t3_edges.frag
+++ b/Polyhedron/demo/Polyhedron/resources/shader_c3t3_edges.frag
@@ -1,12 +1,22 @@
 #version 150
 in vec4 color;
+in float dist[6];
 flat in vec2 subdomain_out;
+uniform bool is_clipbox_on;
 uniform bool is_surface;
 uniform vec4 is_visible_bitset;
 uniform bool is_filterable;
 out vec4 out_color;
 void main(void) 
 { 
+  if(is_clipbox_on)
+    if(dist[0]>0.0 ||
+      dist[1]>0.0 ||
+      dist[2]>0.0 ||
+      dist[3]>0.0 ||
+      dist[4]>0.0 ||
+      dist[5]>0.0)
+        discard;
   if(is_filterable)
   {
     uint domain1 = uint(subdomain_out.x);
diff --git a/Polyhedron/demo/Polyhedron/resources/shader_c3t3_edges.vert b/Polyhedron/demo/Polyhedron/resources/shader_c3t3_edges.vert
index 9d00649a829..60f51ff758a 100644
--- a/Polyhedron/demo/Polyhedron/resources/shader_c3t3_edges.vert
+++ b/Polyhedron/demo/Polyhedron/resources/shader_c3t3_edges.vert
@@ -5,12 +5,36 @@ in vec2 subdomain_in;
 uniform  mat4 mvp_matrix;
 uniform  vec4 cutplane;
 out  vec4 color; 
+out float dist[6];
 uniform  float point_size;
 flat out vec2 subdomain_out;
+uniform bool is_clipbox_on;
+uniform mat4 clipbox1;
+uniform mat4 clipbox2;
+
+void compute_distances(void)
+{
+  for(int i=0; i<3; ++i)
+  {
+    dist[i]=
+    clipbox1[i][0]*vertex.x+
+    clipbox1[i][1]*vertex.y+
+    clipbox1[i][2]*vertex.z +
+    clipbox1[i][3];
+    dist[i+3]=
+    clipbox2[i][0]*vertex.x+
+    clipbox2[i][1]*vertex.y+
+    clipbox2[i][2]*vertex.z +
+    clipbox2[i][3];
+  }
+}
+
 void main(void)
 {
   subdomain_out = subdomain_in;
   gl_PointSize = point_size;
   color = vec4(colors, vertex.x * cutplane.x  + vertex.y * cutplane.y  + vertex.z * cutplane.z  +  cutplane.w);
+  if(is_clipbox_on)
+   compute_distances();
   gl_Position = mvp_matrix * vertex;
 }