Undergrad How Can I Achieve a Non-Direct Reflection Effect on Plexiglass at 90 Degrees?

[Hamedi]

Hi. I want a figure, human, to be reflected on the other side of a plexiglass. Simple enough. But i want the glass to be positioned exactly at 90 degrees, but I want the figure not to reflect directly over thr glass but to be reflected on the other side, as if I've put the glass in a 45 degree angle. For example if the figure is positioned at (-3x,-3y) i don't want it to reflect to (3x,-3y) but to (3x,3y). Consider the Y line as the plexiglass. How can I achieve that effect?

 

[phinds]

I find your description confusing. Please draw a diagram.

 

[Hamedi]

The first picture is the normal reflection rule on the glass which is the line drawn in the middle. The green dot is the light source, the orange one its reflection. In the second picture, the left dot is the same source, but I want it to be reflected on the right side where the right dot is (around that area). Without the plexiglass changing its angle.

 

[phinds]

In neither case do I see this as "reflection", unless you mean that the orange dot represents where the green object appears in the plexiglass to an observer at the green dot.

 

[Hamedi]

In neither case do I see this as "reflection", unless you mean that the orange dot represents where the green object appears in the plexiglass to an observer at the green dot.

To an observer at the glass not the green dot. The observer looking through the plexiglass sees the orange dot as the reflection of the green dot.

 

[A.T.]

but I want it to be reflected on the right side where the right dot is (around that area).

If you only care about that single dot, just place the mirror in the middle between it and its desired virtual image, oriented perpendicularly to the line connecting them.

But if you care about an extended object, including its orientation, then you need to provide more information.

 

[DaveC426913]

To an observer at the glass not the green dot. The observer looking through the plexiglass sees the orange dot as the reflection of the green dot.

Help us help you.

Your diagram needs to include where the observer is. "at the glass" is insufficient since, depending on where they are at the glass, the reflection will appear in a different place.

Rather than a screenshot of a compass, or whatever that is, a hand-drawn sketch with labels would be much more useful.

 

[Hamedi]

The second pic contains an observer(the blue circle), a plexiglass in front of it at a position of 9p degrees. A light source (the green dot) which is blocked by a brown line (cardboard or something). The orange dot is the reflection of the light source lighting the actual object(the green dot). The first pic is where I want the object to be reflected. Under the light source cannot be seen by the observer. And the right side of the glass, you can imagine as a stage. Are you at all familiar with the pepper's ghost illusion? That's what I want to achieve, except that I want the glass to be at 90 degrees, not 45.

 

[A.T.]

except that I want the glass to be at 90 degrees, not 45.

If the glass orientation is fixed, what can be adjusted at all here?

 

[Hamedi]

I would like to know if there are other materials that I can use. Or if I can coat the glass with a high refraction index sheet or something that can help me achieve the effect. The glass orientation is fixed, the object is fixed(or might move a step or two), but the overall production can have things added to it as long as they don't block the observers' view of the stage.

 

[DaveC426913]

It is vital that we understand the function and the context of your ask.

This is the best I can make of your description.
Is it about right?

You're not going to like it. At the very least, you're going to need a mirror between object and apparition of object. i.e. the dotted magenta line.

 

[Hamedi]

It is vital that we understand the function and the context of your ask.

This is the best I can make of your description.
Is it about right?
View attachment 354458

You're not going to like it. At the very least, you're going to need a mirror between object and apparition of object. i.e. the dotted magenta line.

That's 99 percent accurate, thanks for the effort. But the object is the same place as the light source, the partition actually blocks the object from being seen. The yellow light is shone from the ceiling, so the yellow light and the red object in your demonstration are actually in the same place, left that is. And another thing, for the effect to take place, and for the observer to be able to see it, it has to be reflected through the plexiglass.

 

[DaveC426913]

That's 99 percent accurate, thanks for the effort. But the object is the same place as the light source, the partition actually blocks the object from being seen. The yellow light is shone from the ceiling, so the yellow light and the red object in your demonstration are actually in the same place, left that is.

OK, that changes things.

I've given everything single letter labels since I suspect we'll be talking geometry pretty soon.

And another thing, for the effect to take place, and for the observer to be able to see it, it has to be reflected through the plexiglass.

Why? What do you care how the effect is produced as long as it works on the audience?

I think the problem is that you are asking for something that can't be done the way you want it. You're going to need mirrors where you don't have mirrors. And yes, they're going to have to be 45 degrees to the angle of your walls.



I can see a problem that going to arise regardless of the solution. The apparent path length A-G is going to appear to the audience as long as the actual path length A-?-O. If A-O is longer than A-G (say with multiple mirrors), the apparition is going to look too far away.

 

[Hamedi]

I'm ok with having mirrors, I just don't want the audience to notice them. The stage is supposed to be a kitchen, and the plexi, the glass door to the garden or something. I'm just saying if the object is not reflected through the plexiglass, the audience wouldn't see it on the stage, that's why the partition doesn't stretch all the way to the plexiglass, because then the audience wouldn't see anything.

What you say is a problem, yes. The length of both paths has to be calculated.

What about refraction? Can that help?

 

[DaveC426913]

I'm ok with having mirrors, I just don't want the audience to notice them. The stage is supposed to be a kitchen, and the plexi, the glass door to the garden or something.

Yes. You do that by ensuring nothing in the reflection is visible (i.e. is black) except the object.

I'm just saying if the object is not reflected through the plexiglass, the audience wouldn't see it on the stage...

That's a supposition. Your plexi setup is for a standard reflection scenario, but your ask to for a non-standard scenario. You may have to resort to other methods to get the effect you want.

because then the audience wouldn't see anything.

Naturally, any solution we come up with is predicated on ensuring the audience sees the effect as desired. But don't put unnecessary constraints on the solutions if they're not actually part of the requirement.



Question: is the plexi used for any other purpose or effect in the show? IOW, is this the only effect that the plexi is required for? What if, hypothetically, we found a solution that did not make use of that plexi in that location? Could you ditch it?

 

[Hamedi]

I could think about it, but I want there to be a glass between the audience and the actors so they don't see them too clearly, like a fourth wall in theater, but actually placed there, to point out the Platonic idea of the world of forms, things like that. And at the end of the play, the actors open that glass door and are confronted with the audience. Something like that.

I heard that materials with high refractive index, near 2, can refract the light in a way that the ghost of the object appears where I want it to appear. But I don't know if there are thin sheets of them available for over-the-counter purchasing, in orser to coat the plexiglass with it.

 

[DaveC426913]

Does the plexi have to be vertical? Any possibility that it could be tilted away from the audience by 10 or 20 degrees?

 

[Hamedi]

It would give the scene a kind of perspective I'm not looking for.

 

[Tom.G]

Sounds like a hologram of the Object might be made to work.