I'm trying to reach a render like the one on the image below. It's a prism as you can see, and I already made the elements, but the reflections aren't the same.

Maybe it's the material, but I do not know. I already tried changing the object's position and lighting, but it didn't help. So I think it could be the material

blender with prism object

  • 3
    $\begingroup$ Could you post a .blend file for testing? $\endgroup$ Feb 10 '15 at 16:28
  • $\begingroup$ Better lighting and add a bevel to the prism maybe. Working on a file . . . $\endgroup$
    – VRM
    Feb 10 '15 at 16:32
  • $\begingroup$ your prism looks like there's an empty space inside, your ref doesn't. play with IOR. and plug nodes outputs to same colored inputs. $\endgroup$
    – Bithur
    Feb 10 '15 at 16:37
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    $\begingroup$ the rainbow ray could be nicer with some transparency and using a color ramp to smoth colors transitions. You could also add a ground plane. $\endgroup$
    – Bithur
    Feb 10 '15 at 16:44
  • $\begingroup$ I gave some tips on reflections and shading a little time ago. Perhaps they could help you? $\endgroup$ Feb 10 '15 at 17:14

There are several basic issues with your scene, the first one I want to address is your Prism. It is not detailed enough, so there is not a large enough number of angles to bounce the light. Add a Bevel modifier, and a Subdivision modifier to your mesh, and then fix your material to be just a Glass BSDF node with an IOR of 1.44-1.90 (depends on personal preference, this is the realistic range of glass).

The prism is the most important part of the scene, so take your time. This should be something like what you end up with:

Prism Wire

Now model the light beams. I have the white one coming in, and curving slightly out the other side (artistic license, not technically correct). I also have them overlapping, so that in the material I can fade from one beam into the next. Like so:

Prism beam

Now work on the materials, I set mine up like this:


White beam nodes


Spectrum Nodes

Notice that you may need to change mapping values for both materials. Also, I unwrapped the Spectrum mesh and am using the UV map to map the Color Ramp just to give some more control.

Render Result

Prism Render

Now that the basic scene is setup, it is just a case of tweaking lighting and the prism until you have the desired result.

  • $\begingroup$ Thank you! a last question, can you make that 'rainbow' with transparent/diffuse borders? $\endgroup$
    – beavoru
    Feb 10 '15 at 19:37
  • $\begingroup$ You can, I updated the answer. $\endgroup$
    – VRM
    Feb 10 '15 at 19:44

Your material setup is wrong. On first glance you are feeding shader output to glass node color input.

Leave only 1 glass node connected to Shader output, delete the rest.

If you then need more reflections you can mix in a Glossy shader with Fresnel node.

  • $\begingroup$ That helped a lot! thank you! but what about the 'curved reflections' inside the Triangle/Piramid? $\endgroup$
    – beavoru
    Feb 10 '15 at 16:45
  • 2
    $\begingroup$ i think it's the spot being refracted through the prism $\endgroup$
    – Chebhou
    Feb 10 '15 at 16:47
  • 1
    $\begingroup$ @beavoru either the prism in reference pic doesnt have flat surfaces or the ribbons themselves are curved. Then you should get also a curved reflection. $\endgroup$ Feb 10 '15 at 16:51
  • $\begingroup$ Thank you, i'm already adding more geometry, but still i need to fix the interior parts of the geometry :) $\endgroup$
    – beavoru
    Feb 10 '15 at 16:53

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