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In the Cycles node editor, for materials, you can get some information about the object, which the material is being applied to, by using a Geometry node.

Among others, you can get the objects Normal and... it's True Normal. This suggests that the first is fake or not as accurate, which makes no sense. This leads me to my question - what is the technical difference between an object's Normal and it's True Normal?

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  • $\begingroup$ My first thought is that Normal includes any normalmap or bumpmap and True Normal gives you the normal of the actual geometry. I'm guessing here, so I won't give this as an answer. $\endgroup$
    – user7952
    Dec 20, 2014 at 19:41
  • $\begingroup$ @SixthOfFour I looked it up on the Blender Wiki, and it looks like you are correct. $\endgroup$
    – J Sargent
    Dec 21, 2014 at 3:04
  • $\begingroup$ @NoviceInDisguise I've already read your answer, and upvoted it. ;) $\endgroup$
    – user7952
    Dec 21, 2014 at 3:08
  • $\begingroup$ @someonewithpc Could you please accept the answer? Or does it not answer your question? $\endgroup$
    – J Sargent
    Apr 14, 2015 at 18:32

1 Answer 1

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The Blender Wiki states that

Normal = Shading normal at the surface (includes smooth normals and bump mapping).

True Normal = Geometry or flat normal of the surface.

The normal value takes into account your shading technique, while the true normal uses the actual face direction.

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  • $\begingroup$ Is there any other way to influence the normal in blender? I thought it was effectively normal = smooth shaded normals (if enabled), and true normal = flat shaded normals. $\endgroup$
    – gandalf3
    Dec 20, 2014 at 20:45
  • $\begingroup$ That is basically it, the normal Normal includes Bump Mapping, however. $\endgroup$
    – J Sargent
    Dec 21, 2014 at 3:02
  • $\begingroup$ Does this mean, then, that true normal and normal output the same value if the object has flat shading and uses no normal map? $\endgroup$ Dec 16, 2021 at 13:50
  • $\begingroup$ Because it looks like it's a bit more complicated than that. $\endgroup$ Dec 16, 2021 at 13:53
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    $\begingroup$ @mqbakamqbaka My understanding is that they will be functionally the same, which lines up with my testing and usage. However they may use different methods to achieve the same/similar result. $\endgroup$
    – J Sargent
    Dec 28, 2021 at 19:24

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