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How would I get a one way glass effect?

AnotherUserNameAnotherUserName Posts: 2,727
in The Commons

Hi All,

Im wondering how I would capture reflections in the viewing side of one way glass. Just using a glass shader is not achieving the look im going for.

Imagine a very brightly lit operating room. This is the room that is on the mirror side of the one way glass. On the other side is the observation room. The observation room is dark with the exception of computer monitors and maybe a small table lamp. I want to capture some reflections of the people that are in the observation room.

Any thoughts?

Comments

  • TSasha SmithTSasha Smith Posts: 27,260

    Hmmm good question.  So you want a glass that is transparent but still reflective.  Something like seeing the reflection of someone looking out the window at her boyfriend but she is inside and he is outside.  I am not at my computer but will try to figure it out when I get home.

    First some possible stupid questions;daz studio or poser or other?  Which renderer being used?  For example iRay instead of 3delight for studio or for poser firefly or superfly?  I need to know in order to help figure it out.  I can tell you poser instructions but if you are using daz studio that would not help. 

  • ScavengerScavenger Posts: 2,674

    I've done what you're trying...what render engine you using?

    snowbeagle.jpg
    3200 x 2071 - 2M
  • ChoholeChohole Posts: 33,604
    edited May 2016
    AnotherUserName said:

    Hi All,

    Im wondering how I would capture reflections in the viewing side of one way glass. Just using a glass shader is not achieving the look im going for.

    Imagine a very brightly lit operating room. This is the room that is on the mirror side of the one way glass. On the other side is the observation room. The observation room is dark with the exception of computer monitors and maybe a small table lamp. I want to capture some reflections of the people that are in the observation room.

    Any thoughts?

    TBH  one way glass doesn't really work that way. The viewing side of it is not really reflective, The glass is coated on the reflective side, and it only works if, as you say, the viewing side is in a darkened room. The light from the bright room reflected from the mirror back into the room itself is much greater than the light transmitted from the dark room, overwhelming the small amount of light transmitted from the dark to the bright room; conversely, the light reflected back into the dark side is overwhelmed by the light transmitted from the bright side.

    We found, when we had them installed in some attendants rooms in areas which could be prone to vandalsim, that if the viewing side was lighted normally you could actually see throught the mirrored side into the viewing room if you stood close to the mirror.

    Post edited by Chohole on
  • AnotherUserNameAnotherUserName Posts: 2,727
    Kulay Wolf said:

    Hmmm good question.  So you want a glass that is transparent but still reflective.  Something like seeing the reflection of someone looking out the window at her boyfriend but she is inside and he is outside.  I am not at my computer but will try to figure it out when I get home.

    First some possible stupid questions;daz studio or poser or other?  Which renderer being used?  For example iRay instead of 3delight for studio or for poser firefly or superfly?  I need to know in order to help figure it out.  I can tell you poser instructions but if you are using daz studio that would not help. 

    I am using daz and iray.

  • AnotherUserNameAnotherUserName Posts: 2,727
    Scavenger said:

    I've done what you're trying...what render engine you using?

    Im using iray.

  • AnotherUserNameAnotherUserName Posts: 2,727
    Chohole said:
    AnotherUserName said:

    Hi All,

    Im wondering how I would capture reflections in the viewing side of one way glass. Just using a glass shader is not achieving the look im going for.

    Imagine a very brightly lit operating room. This is the room that is on the mirror side of the one way glass. On the other side is the observation room. The observation room is dark with the exception of computer monitors and maybe a small table lamp. I want to capture some reflections of the people that are in the observation room.

    Any thoughts?

    TBH  one way glass doesn't really work that way. The viewing side of it is not really reflective, The glass is coated on the reflective side, and it only works if, as you say, the viewing side is in a darkened room. The light from the bright room reflected from the mirror back into the room itself is much greater than the light transmitted from the dark room, overwhelming the small amount of light transmitted from the dark to the bright room; conversely, the light reflected back into the dark side is overwhelmed by the light transmitted from the bright side.

    We found, when we had them installed in some attendants rooms in areas which could be prone to vandalsim, that if the viewing side was lighted normally you could actually see throught the mirrored side into the viewing room if you stood close to the mirror.

    Interesting. Another Hollywood myth debunked!

  • TSasha SmithTSasha Smith Posts: 27,260

    I can see my blurry reflection on the glass of the mall while I stand outside on a cloudy day.  I can see the food court well but there is an overlay of the outside.  It is not any special glass to my knowledge but my reflection is there while I can look inside.

  • father1776father1776 Posts: 982

    if your a builder, you could make a mirror from a 1 sided polygon, one direction has a visable texture...ie mirror, the other direction doesn't show up at all

    so..you sandwich a clear glass polygon behind it.

     

    Might work

  • AnotherUserNameAnotherUserName Posts: 2,727

    I suppose that one way glass is not necessary for an overall look. Thats just what type of glass it would be in the fiction. Im really just trying to get some cool reflections... assuming my video card doesnt melt.

  • AnotherUserNameAnotherUserName Posts: 2,727
    edited May 2016
    father1776_5775a1855d said:

    if your a builder, you could make a mirror from a 1 sided polygon, one direction has a visable texture...ie mirror, the other direction doesn't show up at all

    so..you sandwich a clear glass polygon behind it.

     

    Might work

    Hmmm. Worth experimenting with.

    But then I would reflect the overhead lights. The operating room is using some obnoxious flourescents so I think that the mirror might overpower the lighting.

    Post edited by AnotherUserName on
  • ScavengerScavenger Posts: 2,674

    Checking back, looks like I used 3Delight on that one, playing with the reflectivity slider of the glass pane.

    I also used a few layers in photoshop to intensify the reflection where I wanted (the tree/girl) and lessen it where I wanted the outside more (the snowman, dog).

  • L'AdairL'Adair Posts: 9,479

    You could "cheat."

    Render the primary scene with the glass and reflections. Then render the same scene with the glass removed, using the subdued lighting in the room "behind" the "mirror." (It might work better if the "operating room" is empty: rendering faster, and easier to mask.) Layer the images in a program like Photoshop, with the primary scene on the bottom. Mask out the area other than the room behind the mirror, Then fiddle with the blend mode and opacity levels until you get the effect you're looking for.

  • AnotherUserNameAnotherUserName Posts: 2,727
    L'Adair said:

    You could "cheat."

    Render the primary scene with the glass and reflections. Then render the same scene with the glass removed, using the subdued lighting in the room "behind" the "mirror." (It might work better if the "operating room" is empty: rendering faster, and easier to mask.) Layer the images in a program like Photoshop, with the primary scene on the bottom. Mask out the area other than the room behind the mirror, Then fiddle with the blend mode and opacity levels until you get the effect you're looking for.

    I was thinking about that. Im probably going to have to composite the whole thing anyhow simply because there will be alot of characters in it.

  • CybersoxCybersox Posts: 9,277

    There are different kinds of reflective glass, which serve different needs.  Some versions are, indeed, reflective on both sides.  Others are mirrored on one surface only and appear as a dark glass when viewed through the non-mirrored side.  It really depends on how the mirror is manufactured.  What Kulay Wolf is describing sounds like a sheet of reflective mylar applied to standard glass.  That's one of the cheapest ways to make a two way mirror, but as the mylar has to be held on with an adhesive, there's a loss of optical clarity.  At the other end of the optical purity scale there's what's called a pelicle, which is used a lot for visual effects work, but is partially transparent from either side and as thin as possible in order to minimize double reflections.   

     

    .      

  • LeatherGryphonLeatherGryphon Posts: 12,090

    Interesting article here on new technology: https://www.sciencenews.org/article/light-filter-lets-rays-through-only-one-direction

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