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How i can add a RGB Curve node, like this example? I want to improve colors of my PLY mesh. (This screenshot is not mine, I've found in this forum.) RGB Curve node

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  • $\begingroup$ I'm not too sure what your question is.. What happens when you try to add it? (where are you stuck?) $\endgroup$ – gandalf3 Sep 16 '15 at 7:07
  • $\begingroup$ This screenshot is not mine, I've found in this forum. $\endgroup$ – sborfedor Sep 16 '15 at 7:08
  • $\begingroup$ @sborfedor are you still using Blender Internal as a renderer (and not cycles)? $\endgroup$ – zeffii Sep 16 '15 at 7:14
  • $\begingroup$ yes @zeffi, Blender Internal! $\endgroup$ – sborfedor Sep 16 '15 at 7:17
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As mentioned in the previous post, ideally you fix the input file because for whatever reasons the object was imaged under poor lighting conditions or the software used might have a mode to adjust the brightness of the polygon/vertex colours and it was set to darken.

Regaining the fidelty / vibrance of the colours is tricky and the techniques used might produce unsatisfactory results.

One fast way for Blender Internal is to use Ambient Occlusion and Environment Lighting, from the World tab. You'll notice the result is a little blown out (as if over exposed) if the guy is wearing a light pink shirt.

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Blender Internal's materials also has a Nodes mode, and it supports Vertex Colors. It allows you to adjust the colours with an RGB Curve too, and you don't need to enable Ambient Occlusion or environment lighting

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Or maybe a hue / saturation node:

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Anything you do to make it render nicely won't be a true representation of what the output will look like if it's 3d printed (I think you are doing this to render product shots?) -- unless you somehow modify the Vertex Color map.

You can bake to Vertex Colors using the Bake feature set to 'Full Render'. I would create another Vertex Color layer and set that to active in the panel, before doing a bake. This will prevent bake from over-riding your original.

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bake:

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    $\begingroup$ one solution might be to use a script to find the color components of the weakest and most energetic vertex color, and create a duplicate vertex color layer with all vertex colors adjusted to give a greater dynamic range. $\endgroup$ – zeffii Sep 16 '15 at 7:42
  • $\begingroup$ Thanks zeffii! I've found the RGB Curve node and I've modified the curve, but the mesh still dark. How to apply the curve modification? Is there an "OK" button somewhere? $\endgroup$ – sborfedor Sep 16 '15 at 8:54
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    $\begingroup$ this only affects how it renders. it does not adjust the underlying vertex color data. I'm not aware of any convenient way to adjust a vertex color layer according to a curve.. $\endgroup$ – zeffii Sep 16 '15 at 9:47
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    $\begingroup$ if you can figure out a nice formula to adjust the vertex_color brightness, then you could use something like this script: gist.github.com/zeffii/4b2502e6300bccf48e14 $\endgroup$ – zeffii Sep 16 '15 at 9:54
  • $\begingroup$ While this is a very useful answer, I think it is more suitable fot this question: blender.stackexchange.com/questions/38577/…. They probably should be merged (answers too if you agree). $\endgroup$ – Carlo Sep 16 '15 at 12:39

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