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In cycles render, I would like to make a textured surface emit light while the texture is still showing. Tried various methods (some suggested here) but haven't really found a solution. The ideal resolution would be if I could make the surface emit light but not lighting itself (so the texture remains visible). Is something like that possible?

This is what I have:

enter image description here

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final

You can mix your texture with Emission Shader through Light Path > Is Camera Ray. This way you can have basically two shaders at once.

You can change Emission Color and plug base color texture to it.

nodes

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  • $\begingroup$ oh yes of course ;) $\endgroup$ – moonboots May 16 '19 at 12:49
  • $\begingroup$ This has done it; yours is the correct answer. Thank you! $\endgroup$ – Gergely Kovacs May 17 '19 at 7:25
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So what have you tried so far? Have you tried to duplicate your object, give the copy a higher Emission Strength and make it invisible to the camera?

  • Create a copy of your object and duplicate its material.
  • Scale the copy or move it above the original object.
  • Go in the Properties panel > Object > Display and choose Maximum Draw Type > Wire to make it easier to manipulate in Object mode.
  • Go in the Properties panel > Object > Cycle Settings and deactivate the Camera option to make your object invisible in Render mode.
  • Give this copy a higher Emission Strength so that it emits more light than the original and can enlight its environment.

enter image description here

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  • $\begingroup$ I consider duplicating the object a messy hack; so, no, I have not considered it. In all honestly, if there is no elegant solution, I'd rather place a light source inside my object and make the emitting surface slightly transparent, or even place an area light right in front of it. $\endgroup$ – Gergely Kovacs May 16 '19 at 7:59
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    $\begingroup$ sure it's not perfect, it's just a quick trick that will give a good result most of the time though. About what you say, for example if you use an area light it won't project the texture all around, I thought you wanted this, so maybe putting a light source inside your object is the best (and most realistic) solution in your case... $\endgroup$ – moonboots May 16 '19 at 8:03
  • $\begingroup$ Actually I think Cgslav has given the elegant solution ;) $\endgroup$ – moonboots May 16 '19 at 12:53
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... algorithms model diffuse inter-reflection which is a very important part of global illumination

You are not understading blender node system and global illumination principles.

An important concept to understand when building node setups is that of the shader socket. The output of all surface and volume shaders is a shader, describing lighting interaction at the surface or of the volume, rather than the color of the surface.

  1. Do not use texture as shader: use diffuse or other to simulate the physical properties of the material.

  2. You need to iluminate textured surface by other light source, world or volume.

Self illuminated Self illuminated

Inderect illuminated by volume and world background for a 0.01 white Inderect illuminated by volume and world background for a 0.01 white

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