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Right now, I have made two mirrors facing each others and a tunnel in the middle (like in viewport at the bottom-left corner of the pic). So the reflections will bounce back and forth as many times as glossy bounce limit, making it seems the tunnel goes way longer than it actually is.

enter image description here

What I want to achieve is to make the reflections rotate/twist a certain amount every time it reflect from a mirror. So it would seems like tunnel goes in spiral.Also, the spiral effect will hide some repetitions from reflections. I'm wondering if there's a way to achieve this by manipulating normals on the mirrors.

The goal is to make a scene looking up from inside of a tornado. The walls will be converted to volumes and displaced to make it seems like clouds and twist it to make it spiral up.

In real world, such effect can be mimicked by having a lot of grooves that radiate from the center of the mirror. In each groove, the surface is tilted a few degrees. I'm trying to make a abstract scene that will look like insides of a tornado. The wall of the tunnel will be displaced or made volume. I'm trying not to use too many geometries by using mirrors and make it less repetitive by making it look like a spiral.

[edit]Here in this screenshot is how the exact effect is achieved by modelling the geometry of the mirrors. In the picture, cylinder is a normal cylinder but it spiral out because of reflections. How can this be done just by manipulating normals?

enter image description here

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  • $\begingroup$ There is no real world scenario with this working, is there? What objects are reflected there? Where does the light come from? What do you want to show with this render? $\endgroup$
    – Martynas Žiemys
    Commented Jan 11 at 7:16
  • $\begingroup$ @MartynasŽiemys In real world, such effect can be mimicked by having a lot of grooves that radiate from the center of the mirror. In each groove, the surface is tilted a few degrees. I'm trying to make a abstract scene that will look like insides of a tornado. The wall of the tunnel will be displaced or made volume. I'm trying not to use too many geometries by using mirrors and make it less repetitive by making it look like a spiral. $\endgroup$
    – Pyae
    Commented Jan 11 at 11:44
  • $\begingroup$ Hello, Pyae, welcome.. .. your question would be more self-contained and clearer, if you edited a version of your comment into the post. $\endgroup$
    – Robin Betts ♦
    Commented Jan 11 at 13:11
  • $\begingroup$ @Pyae OK, that makes it a bit clearer, however you still skipped the most essential part - what would be reflected in the mirror and what the image should show. You also need a light source. If it can be done with grooves, you can make them with geometry or by manipulating normals - bump or normal map. $\endgroup$
    – Martynas Žiemys
    Commented Jan 11 at 14:14
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    $\begingroup$ Thanks @RobinBetts, I've added more information to my post. $\endgroup$
    – Pyae
    Commented Jan 11 at 14:14

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I was curious about doing this with a refraction mesh, rather than with the normals of a mirror, and I believe this may be what you're after:

enter image description here

I'm doing some weird things in this "mirror tunnel". The selected mesh is a refraction mesh with impossible normals, rotated based on their polar coordinates.

Realistic lenses have backfaces that kind of undo the refraction when the rays leave the lens, but this doesn't, which means that you get successive refraction with each bounce through the tunnel.

If something like this is what you're after, there's plenty of room for playing around with it.

Looks like you can do something similar by giving one of your mirror caps these same impossible normals:

enter image description here

Don't want both of the mirrors to have the same material though. One of the caps should just be a regular, flat mirror. Not entirely sure why.

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  • $\begingroup$ Yeah, this is definitely what I'm looking for. Achieving it through nodes give so much control over the effect. Thanks. I'll also try similar nodes like yours on normals too. $\endgroup$
    – Pyae
    Commented Jan 12 at 16:34

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