Diamond RenderNode Setup Lighting Setup

Does anybody know why there are dark patches in the corners of the pear shaped diamonds in my renders? I have attached the node set up of the diamonds (which i followed from a tutorial) incase there is anything wrong in there, and also the lighting setup for the same reasons.

I have tried spinning the ring and no matter which angle it is rendered at there is still darker patches, and i have also used a boolean to make sure there are no intersecting pieces of 'metal mesh' on the 'diamond mesh'.

Is it just a lack of light behind the claws and the shadows that are cast causing the diamond to reflect the darkness or are there other problems?

  • 3
    $\begingroup$ What are your Render > Light Parhs > Max Bounces, and > Transparency set to? One of the first things to check is if you're running out of ray before a light-source/color is reached. $\endgroup$
    – Robin Betts
    Commented Aug 18, 2018 at 15:36

1 Answer 1


It would be easy if you uploaded the blend file, or drawed where are the dark patches, because I can't see them in your image, but I simply think that the "Dark Patches" you mentioned are simply reflections from the area around your scene that has not a background. Think about it, the left and right portion of your scene doesn't have anything for the ring to reflect, if you are not using a HDRI, which I think you're not, then the dark patches are simply reflections of empty areas.

As for the shader you have, I don't know why you have 4 different colored glass shaders adding on top of each other, might be something to do with that, it should be easier to reacreate the same material with a Principled BSDF shader.

Also your top image is a rendered one, in which engine you are rendering? Cycles or Internal? That might change things as well, your rendering options like bounces can affect that kind of thing too, that's why it's much easier if you uploaded your blend file.

But I hope this answer helped you,

  • $\begingroup$ I am using a HDRI, but there are black sections in the HDRI which may be the problem, also, the glass shaders are to replicate the different colour refractions that diamonds produce to increase realism. I am rendering in the blender cycles engine & finally i wasnt aware of the ability to upload the blender file as i am new to BSE but i appreciate you taking your time to help! $\endgroup$
    – Josh May
    Commented Aug 18, 2018 at 15:53

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