I've been following the discussions on this board for quite some time, simply because it's rather fun to see what the HBs will come up with next, but I've never written anything here before.

However, after seing the excellent photos in this thread, demonstrating the shadow effect, I realized this bordered on my field of expertice. I've been working with computer animation and special effects for quite some time, and I realized this would be a perfect opportunity to use this knowledge.

What I did was this: I downloaded the image of the two astronauts with different shadow length from Cosmic Dave's site. I then applied the same techniques used to integrate live action and CG data in motion pictures (in this case front projection and tracking), and created a 3D model of the shading situation in the picture.

Actually, I created two shading situations. One for the scene lit by the sun, and one for the scene lit by a stage light.

Here are the results:


Original image


Sun lit scene


Stage light lit scene

Of course, this is just a quick lighting test, and it's not perfect. Still, it clearly shows a couple of things:

First, the shadow length is wrong in the scene using the stage light, but correct in the sun lit scene (if the shadow length of the second astronaut should be correct, the shadow of the first will be wrong, and the other way around, when using the stage light).

Second, the light from the sun create sharp shadows (just like in the original image), while the stage light crate fuzzy shadows.

Here is the LightWave scene for download, if anyone wants to examine the scene setup:

Scene

There are free scene viewers available on the net, and the scene file itself is readable by a human, so anyone should be able to verify that this is not a fake. The reason I include it here is that I would very much like Cosmic Dave or anyone from his camp to look at it and tell us which one they think look more like the real photo - the sun lit or the stage light lit scene - and in order to do so it is necessary that they can verify that the scene setup is indeed correct.