I was trying to create a hall of mirrors. A long hall with all the walls, floor and ceiling as mirrors. Some unexpected results in the render.

Create hall 2000m long, 5m wide and 5m high. Wall, floor, ceiling texture is Glossy Bsdf with roughness=0. Try also Principled Bsdf, no difference.

Place point lights inside every 25m, mid-width and mid-depth. 3000W and .25m radius. Camera setup at 1600m looking down the long hall.

In Viewport Shading see the hall as nice mirror look. Expect the Cycles render of the interior to be the same. Unexpected black/white result rendered given.


  • 2
    $\begingroup$ What do you expect the perfectly smooth mirrors to reflect? The only thing visible to them is the lights. The result is exactly what it should be. If by "viewport shading" you mean "Material Preview": It's only an abstract preview, not what you render in your scene. $\endgroup$
    – L0Lock
    Oct 30, 2023 at 1:43
  • 1
    $\begingroup$ Please show us a screen-grab of the acceptable render in the viewport ? That would help us clue in to what you want. Is your render-version missing a World HDRI environment? , (That's provided for you automatically for preview in the viewport, if 'Scene World' is unchecked) $\endgroup$
    – Robin Betts
    Oct 30, 2023 at 6:35
  • $\begingroup$ You have practically modeled a huge "nanotube" here, in which the light is reflected for all eternity, but never comes out again. This is exactly what Vantablack does on the microscopic level. The result is the blackest material on earth. $\endgroup$
    – Blunder
    Oct 30, 2023 at 14:34
  • $\begingroup$ What you actually "see" in the real world is the remains of light absorption. A light source emits light, the light hits a surface, gets absorbed, and is partially reflected. What then finally meets your eyes is what you see. If you look straight into a light source, it will blind you, all you see is a bright glare. If no light at all is reflected, all you see is pitch-black darkness. $\endgroup$
    – Blunder
    Oct 30, 2023 at 14:35
  • $\begingroup$ Here are a few videos about similar experiments in real: I Painted My Entire Room With Musou Black—The World's Blackest Paint -- Painting My Entire Room With The World's Brightest Paint...Then Turning on a 100,000 Lumen Light! -- I Built An Entire Room Made Completely Out of Mirrors! -- In a box with only one light and mirrors that reflect 100% of the light, I would really only expect a bright glare like shown here: Blender: What it looks like inside a Mirror Box $\endgroup$
    – Blunder
    Oct 30, 2023 at 14:54


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