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Using Cycles. I have lit and rendered 20 different objects with the same lighting set up. Now using same setup to render a glass object, as part of the series. However the emmissive plane used for lighting is now showing up in the glass reflection of this particular shot.

I don't want to change the lighting now. Needs to be uniform across the previous 20 renders.

Tried turning off that light object's Glossy ray visibility, but that made the glossy objects around the glass too dark.

Is there another way to keep the scene just as well lit, but remove the plane's reflection from the glass?

I've got the impression from this post that 'render layers' might have to be involved, but I'm quite new to blender, a bit short on time, and hoping for simpler method, if anyone knows.

Reflection

nodes

glossy rays off vs refraction material

Trying Leon Cheung's method:

enter image description here

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  • $\begingroup$ related: blender.stackexchange.com/questions/57603/… and blender.stackexchange.com/questions/44649/… $\endgroup$ – cegaton Jul 21 '16 at 6:32
  • $\begingroup$ Changing your glass material to refraction shader ? $\endgroup$ – lemon Jul 21 '16 at 6:49
  • $\begingroup$ @lemon tried just reftraction shader, and mixing refraction with transparency shader, but neither was transparent anymore, it seems, no matter what factor I used to mix the two. Needs to be transparent for background purpose. $\endgroup$ – sliver Jul 21 '16 at 7:16
  • $\begingroup$ glass on the left, refraction on the right : i.gyazo.com/c95c1f7e16df930e96b738e64d9a32c0.png. Think about refraction to be a not glossy glass (only keeps IOR). But as the glossy aspect is lost for every objects, I don't know if it can be an answer $\endgroup$ – lemon Jul 21 '16 at 7:23
  • $\begingroup$ Thanks @cegaton. Wish it worked, but makes my other objects too dark, by turning visibility of glossy rays of emitter off. Attached image to question. $\endgroup$ – sliver Jul 21 '16 at 7:32
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For the emission plane material, you can make use of Sigular Ray to get rid of perfect reflection and transmission.

Comparision:

enter image description here

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  • $\begingroup$ Hello and thanks... that requires some roughness in the glossy shader, am I right ? $\endgroup$ – lemon Jul 21 '16 at 7:42
  • $\begingroup$ @Leon Cheung, your solution looks great, exactly what I want. But my result does not match your result. I posted a screenshot of my results in the question. Any ideas what could be wrong? $\endgroup$ – sliver Jul 21 '16 at 8:39
  • $\begingroup$ @sliver Hmm, maybe you could share the file? That would be really helpful for improving the answer. $\endgroup$ – Leon Cheung Jul 21 '16 at 10:33
  • $\begingroup$ @lemon it seems you are right, I'll have a deeper look. $\endgroup$ – Leon Cheung Jul 21 '16 at 10:37
  • $\begingroup$ I think we missed a big point: Cycles doesn't support per-object light path, which means, you CANNOT disable ray visibility of the emission plane for particular object. So it has to be done with help of render layer, object or material index, and post-composition I'm afraid. $\endgroup$ – Leon Cheung Jul 21 '16 at 12:58
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A complement solution (as the one from Leon Cheung is good) but we start commenting too much below the question.

enter image description here

In order to have transparency, two things are needed :

  • A transparency shader
  • Setting the film to transparent in the render panel

enter image description here

Concerning the node for the glass part :

The refraction shader replaces the glass shader (see it like a non glossy glass). And the transparent shader is needed to have the wanted overall transparency.

enter image description here

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