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In Cycles the Layer Weight node has an output called Facing.

In Blender Internal the Geometry node has an output called Front/Back.

Comparing Facing and Front/Back

Do these perform the same function and just have different names, or are they doing something different?

Thanks

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Do these perform the same function and just have different names, or are they doing something different?

No, they don't. They perform something different:

  • Facing output from Cycles Layer Weight node gives angle of incidence. You can read about this node and how it compares to the Fresnel node here: Relation between Fresnel IOR and Layerweight blend?

    You can make it from scratch in Blender Internal node material like this:

    enter image description here

  • Front/Back output from BI Geometry node is the same as Backfacing output from Cycles Geometry node and gives a binary true/false (1/0) if a face is oriented to the camera with it's normal or not.

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  • $\begingroup$ Thank you, that's helpful. Do you know if there is any way to get Layer Weight data into a BI node setup? Or is "angle of incidence" not applicable in BI? $\endgroup$
    – Mentalist
    Commented Feb 5, 2016 at 14:23
  • $\begingroup$ Thanks for that edit! That's just the info I was looking for! $\endgroup$
    – Mentalist
    Commented Feb 5, 2016 at 15:52
  • $\begingroup$ @Mentalist If this is something useful in BI you can also rephrase the question so it's better searchable to how to get incidence angle in Internal;) $\endgroup$
    – Jaroslav Jerryno Novotny
    Commented Feb 5, 2016 at 16:18
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The Cycles Layer weight node is used to emulate Dielectric materials, useful for example for layering diffuse and glossy shaders to create a plastic material with Fresnel effect. It's used as a factor mask between 2 shaders when they are combined with the "Mix shader" node.

Whereas Geometry node for the blender internal is used for specifying how light reflects off the surface. This node is used to change a material’s Normal response to lighting conditions. Use this node to feed the Normal vector input on the Material node.

Answer So no they are not the same thing.

The weight node affects how 2 shader composite on top of one another. The Geometry node in Blender Internal uses the material's setting to overwrite your mesh's normals.

However there is a Geometry node that is in Cycles that is similar to the Geometry node in Blender internal. I have created a small blend file for your reference.

Also check this video out ... it shows how the Cycles geometry node is used. https://www.youtube.com/watch?v=lOSoGvw97XI

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    $\begingroup$ This is not accurate. The Layer weight node also specifies how light reflects of the surface, and is useful for every material, not only dielectrics. Geometry node has other outputs besides the Normals which gives it far greater usage than you state. $\endgroup$
    – Jaroslav Jerryno Novotny
    Commented Feb 5, 2016 at 10:57
  • $\begingroup$ Well he was specifically asking about "Front/Back" option of the geometry node vs the Layer Weight "Facing" is he not? $\endgroup$
    – hawkenfox
    Commented Feb 5, 2016 at 14:14

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