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Is it possible to fake reflections per object in Cycles? If so, how? (I don't mean one image to appear as background and another to appear in all reflections). I mean using an image on the object mapped to reflection coordinates.

Scenario: I am using an Environment texture in the world shader settings. I have multiple objects each with reflective surfaces, one of which is using the Glass shader, I'd like the glass to reflect as it normally does with the addition of another image. To be able to blend the actual scene (objects+environment maps) with an entirely different environment reflection that isn't part of the scene.

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    $\begingroup$ What exactly do you mean by "Fake reflections"? Do you mean using an image on the object mapped to reflection coordinates? Or control which objects can be reflected and which can't? $\endgroup$ – Greg Zaal Jul 29 '13 at 7:03
  • $\begingroup$ @bmarple, please describe the scenario for this with more detail. $\endgroup$ – zeffii Jul 29 '13 at 7:53
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Expanding on brecht's answer, here is a simple node setup:

enter image description here
A glossy node is used instead of an Emission node to get the "real" reflections in addition to the image. To do this with a Glass node, you will have to separate the glossy and refraction.

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  • $\begingroup$ Is there a way to add glossy roughness to the fake effect? $\endgroup$ – PGmath Jul 10 '15 at 2:29
  • $\begingroup$ @PGmath You could blur the image. If you don't want to blur it externally, you could fake the blur by distorting the mapping coordinates $\endgroup$ – gandalf3 Jul 10 '15 at 7:44
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First you need to render an environment map of the reflected scene:

  • Put the camera in the center of the scene
  • Change it to Panoramic and set the type to Equirectangular
  • Render and save image

To use this image in an object material:

  • Add an Emission node
  • Plug an Environment Texture node into its color
  • Plug Reflection texture coordinates into the texture node
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  • $\begingroup$ it's cool, but it doesn't seem to map the reflection properly. $\endgroup$ – ChameleonScales Dec 6 '16 at 12:58
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You could render each object in the scene separately, then combine them in the compositor. For each render set the enviroment to the desired map.

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