Holograms and shadows

[Melakon]

I was just watching VOY: Renaissance Man, which has a scene near the end where Janeway visits the Doctor in sickbay. He's off-screen for a moment, but his shadow is cast on a wall.

Shadow? He's a hologram, made of photonic projections and force fields, not solid matter. How does a projection of light cast a shadow?

I guess this is a problem ever since holograms first showed up in TNG.

 

[Tosk]

The shadow is just part of the hologram too.

 

[HIjol]

I agree. If the Holodeck is to be a place of accurate reproduction, then shadows should be included. For example, Worf's training program could include hidden opponents that would cast a shadow to clue Worf into where they could be theoretically hiding, or obscured. Just like in a real scenario with real opponents.

If that makes sense!

 

[mos6507]

I never bought the idea of holodecks. It's magic tech, period. Any attempt to hold it up to scrutiny and the whole idea falls apart like a house of cards.

What they should have done is kept the holodeck purely a non-physical simulation. In other words, a 3D game where you can't touch anything and nothing can touch back. But then the holographic doctor wouldn't have been able to perform surgery, in which case he would have had to have been an android, which would have been too much like data.

 

[Tosk]

I never bought the idea of holodecks. It's magic tech, period. Any attempt to hold it up to scrutiny and the whole idea falls apart like a house of cards.

As they say, any sufficiently advanced technology is indistinguishable from magic.

Do you have the same reaction to the Trek use of display holograms, replicators, force-fields, and artificial gravity...or only when you combine them?

 

[Silvercrest]

I never bought the idea of holodecks. It's magic tech, period. Any attempt to hold it up to scrutiny and the whole idea falls apart like a house of cards.

What they should have done is kept the holodeck purely a non-physical simulation. In other words, a 3D game where you can't touch anything and nothing can touch back. But then the holographic doctor wouldn't have been able to perform surgery, in which case he would have had to have been an android, which would have been too much like data.

They could have set it up so that he's non-physical, but he commands all sorts of artificial arms, tools, hyposprays, etc. that extend from the walls.

 

[Ithekro]

If his photons display as opaque, other light source will cause him to cast a shadow.

 

[HIjol]

I was just watching VOY: Renaissance Man, which has a scene near the end where Janeway visits the Doctor in sickbay. He's off-screen for a moment, but his shadow is cast on a wall.

Shadow? He's a hologram, made of photonic projections and force fields, not solid matter. How does a projection of light cast a shadow?

I guess this is a problem ever since holograms first showed up in TNG.

Meant to say this before, Melakon, but there is nothing wrong with your eyes or your noticing of detail!

Nice catch on the Shadows!

 

[TheGoodStuff]

I was just watching VOY: Renaissance Man, which has a scene near the end where Janeway visits the Doctor in sickbay. He's off-screen for a moment, but his shadow is cast on a wall.

Shadow? He's a hologram, made of photonic projections and force fields, not solid matter. How does a projection of light cast a shadow?

I guess this is a problem ever since holograms first showed up in TNG.

In the same way videogame characters have shadows. It is all part of the simulation. The holodeck would suck if it couldn't do something so basic as project accurate shadows.

 

[Melakon]

But the example I gave was the Doctor in sickbay, not the holodeck. Sickbay holo-emitters apparently are only for the Doctor and things like holographic lungs, not full holographic simulations of an environment. It gets more complicated when circumstances involve the holo-emitter which allows a personality program to interact in a real environment with natural light sources. Somehow the hologram is even able to cast shadows in natural sunlight.

 

[CorporalCaptain]

Real holograms are transparent, and therefore cast no shadows.

 

[T'Girl]

If the Doctor is solid enough to slap Paris and pick up objects then of course he would cast a shadow.

If we can see the Doctor, then how in the world would light pass through him? It's not as if he's transparent.

 

[CorporalCaptain]

If the Doctor is solid enough to slap Paris and pick up objects then of course he would cast a shadow.

If we can see the Doctor, then how in the world would light pass through him? It's not as if he's transparent.

As I just said, real-world holograms are transparent, but you can see them. Just because you can see something, that doesn't mean that it's not transparent.

The Doctor isn't a real-world hologram, though.

 

[Melakon]

If the Doctor is solid enough to slap Paris and pick up objects then of course he would cast a shadow.

That was done through the use of selective dynamic force fields, which the holo-character can autonomously control at will, it's not solid physical matter.

The only way I can think of to get around the shadow problem would be to put the holo-character into a scene using blue screen, but that would be prohibitedly expensive to do consistently in a television series.

 

[JirinPanthosa]

You can't see through the Doctor. It'd be weird if he didn't have a shadow.

 

[Vandervecken]

If the Doctor is solid enough to slap Paris and pick up objects then of course he would cast a shadow.

That was done through the use of selective dynamic force fields, which the holo-character can autonomously control at will, it's not solid physical matter.

The only way I can think of to get around the shadow problem would be to put the holo-character into a scene using blue screen, but that would be prohibitedly expensive to do consistently in a television series.

As two other posters have written, the Doctor is opaque. That is sufficient for him to cast a shadow--the computer need do no other complicated wizardry beyond whatever allows the photons in fields that make a Trek hologram to somehow reflect other light so we can see it. If he is a non-mirrored set of surfaces that reflects light then he will cast a shadow like any physical object (which he is, in fact--a physical object, just one made out of photons and fields).

 

[T'Girl]

That was done through the use of selective dynamic force fields, which the holo-character can autonomously control at will, it's not solid physical matter

Okay, if the Doctor's form permits the passage of light, thereby preventing the casting of a shadow, then when the Doctor moves in front of a light we should be able to see it through him.

 

[JirinPanthosa]

Also, if the forcefields can block matter from passing through, why not light? How is one harder to suspend disbelief for than the other?

 

[The Wormhole]

The shadow is part of the simulation. Dr. Zimmerman realized early on in the EMH development how disconcerting someone without a shadow would be and that this could be an unwelcome distraction in an emergency situation where life and death are dependant on split second decisions. Therefore EMHs are equipped with a special algorithm which detects light and the sickbay's holo emitters generate a shadow where its appropriate. The mobile emitter also works on a similar principle, projecting a shadow as appropriate because even in the 29th century sentient races are absolutely freaked by people with no shadows.

During the invention of mobile emitters some suggested the shadows be removed, to make it easier to determine who is flesh and who is photonic. But holograms, feeling their rights were once again being challenged, successfully fought in Federation courts for the right to cast a shadow.

 

[HIjol]

The shadow is part of the simulation. Dr. Zimmerman realized early on in the EMH development how disconcerting someone without a shadow would be and that this could be an unwelcome distraction in an emergency situation where life and death are dependant on split second decisions. Therefore EMHs are equipped with a special algorithm which detects light and the sickbay's holo emitters generate a shadow where its appropriate. The mobile emitter also works on a similar principle, projecting a shadow as appropriate because even in the 29th century sentient races are absolutely freaked by people with no shadows.

During the invention of mobile emitters some suggested the shadows be removed, to make it easier to determine who is flesh and who is photonic. But holograms, feeling their rights were once again being challenged, successfully fought in Federation courts for the right to cast a shadow.

Source, Schmorsch!!!

Immediate. Absolute. Canon!!!

(Note to Mods; I Declare, Under Penalty of the 'Bonz and the Possum, that I have used my "Preemptive Canon Card" in this Post)

Forthwith.