Here is the final version that exports the animation.

Export["/LightCone.gif", Table[
  Graphics3D[{
    {
     Opacity[0.1],
     Table[
      InfinitePlane[{0, 0, z0}, {{1, 0, 0}, {0, 1, 0}}], {z0, {-1, 0, 1}}],
     Red,
     Table[InfinitePlane[{0, 0, z0}, {{1, 0, 0}, {0, 1, 0}}], {z0, {-1 + (-z), -1/2 + (-z), -z, 1/2 + (-z), 1 + (-z)}}]
     },
    {
     {
      Line[{{0, 0, -1}, {0, 0, 1}}],
      Opacity[0.7],
      Cone[{{0, 0, -1}, {0, 0, 0}}, 1],
      Cone[{{0, 0, 1}, {0, 0, 0}}, 1]
      }
     }
    },
   Axes -> True, BoxRatios -> 1,
   AxesEdge -> {Automatic, {1, -1}, Automatic},
   AxesStyle -> {Black, Black, Red},
   AxesLabel -> {"Space (ct)\t", "\tSpace (ct)", "Time (t)\t"},
   Ticks -> {Automatic, Automatic, {{-1, "1 sec in past"}, {0, "Now"}, {1, "1 sec in future"}}},
   PlotRange -> 1.0],
  {z, 0, 0.49, 0.01}]]

BTW this helped me solve a few problems I had:before.

• My original version was inefficient. This is much more efficient as it is using a single Graphics3D function.
• When I was using Animate I had to export as AVI, convert it to WMV and then convert to animated gif. When I exported the gif directly it would only export the first frame. Now I can export the animated gif directly.
• Lastly and most importantly I get only the forward run of the animation. When I used Animate it was generating both the forward and backward animation no matter what options I used.

One more thing, The min value in Table has to be less than the max value. (REF:Table[expr,{i,imin,imax,di}] ) This is not the case for Animate and Manipulate.

Hope this helps some other folks.

Thanks, Sandip

Hi Gianluca,

Thank you. I was not aware of InfinitePlane. With a single Graphics3D, this may allow me to export an animated GIF. I was not able to export an animated GIF with Show[] I was using.

Thanks again,

Sandip