PP2014 - PROPER Mirror Material with Double Reflection (Bagginsbill?)

  • Hi folks,

    Bagginsbill, this could be a fun one for you!

    I'm wondering if it would be possible to create a kind of double reflection on a surface. The conventional mirror material is perfect for general use, but not for odd angles and close-in renders. This is because you not only get the reflection from the silver backing of the mirror, but also a less obvious, ghostly second reflection from the surface of the glass. Not only this, but the reflection is ever so slightly tinted green, which is why reflections through 'infinity tunnels' created with glass mirrors progressively turn more green.

    So, is there a trick for these effects, using a single plane? I know that, ideally, there would be two planes (I would have thought so, anyway), but material room tricks are fun to see when done right!

    I don't have a particular use for this in mind, it's just a fancy I have.

    Cheers. :)

  • @Glen85 why not use a thickened plane for the glass part and another flat plane sandwiched to it with the mirror material? The thickened plane could be slightly refractive with a bit of gloss.

  • Poser Ambassadors

    This is easy in FireFly. You abuse the Bias property.


    I made a double mirror shader but I exaggerated the front (glass) reflection.

    The circled parameters should be reduced.

    The Fresnel_Blend's Index_of_Refraction is here set to 16 but should be 1.6 in production use. This number alters the effective brightness of the glass reflection. Real glass IoR is generally from 1.5 to 1.65.

    The Reflect_2 node's RayBias here is 20 but should be lower, as this controls the separation between the two reflections and I made it really high here to clearly show the double reflection. Note also that my display units are inches and this number depends on your chosen PDU. If you want to be safe and not have to do conversions in your head, set your PDU to inches before you type in my numbers from my screen shots.

    Note also that the Reflection_Color is where I applied a little bluish-greenish tint as it is modulating the base, metal reflection. I used rgb 240, 250, 255.

  • Why don't you have medals, Bagginsbill?! That's brilliant, thank you very much! :D

  • @ghostship That could work if there is room in the mirror prop's frame. Thanks.