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I watched Andrew Price's tutorial on baking in Cycles, and I noticed that after he baked it to an image, he plugged the color output of that image into the color of an emission shader with a value of 1 for it's energy parameter. What is the significance of an emission shader with a value of one?

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An emission shader with a strength of 1 will output the exact same colors as it's given as input.

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Higher or lower strengths will brighten or darken the output.

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  • $\begingroup$ Okay, so if I have an emission shader with the strength of one, it has exactly the same influence as it would other wise? Thanks. (Before it was baked?) $\endgroup$ – Anson Savage Jun 2 '15 at 20:20
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    $\begingroup$ @AnsonSavage Not entirely. It will be practically the same when seen directly, but it will cast light on objects around it differently. $\endgroup$ – gandalf3 Jun 2 '15 at 20:25
  • $\begingroup$ Oh. So the influence it has as an emission shader is not the same as the light that used to be bouncing off that object? $\endgroup$ – Anson Savage Jun 2 '15 at 20:27
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    $\begingroup$ @AnsonSavage It depends. The light from the emission shader is the same as the light which would be reflected into the camera by the shaded object, but not necessarily the same as would be reflected onto other objects. In the case of uniform shaders like diffuse, the emission shader is a very close approximation (the limited resolution of the baked texture and clamping from a format like png or jpg can change the result). However shaders which give very different results depending on angle (such as glossy) this approximation breaks down completely. $\endgroup$ – gandalf3 Jun 3 '15 at 3:34
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    $\begingroup$ @AnsonSavage I have not tested it performance wise, but otherwise the only major issue I've noticed is that when the baked texture is clamped, the light "reflected" (really emitted) from the object is weaker than it should be. I wasn't able to bake a texture to a 32 bit non-clamped float image in order to work around this, it all ends up black. I guess baking to such formats is not supported? $\endgroup$ – gandalf3 Jun 3 '15 at 6:11

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