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I am having an immense issue with using my normal map in blender cycles engine. It works perfectly fine in Blender Render (but I can't get my transparency to work there, so I figured it's time to move to cycles anyway), but not even close in Cycles. It is the exact same model and the exact same texture.

I am VERY new to Blender/3d-modeling, so I don't have any idea where the issue is coming from. The nodes were very straightforward as I essentially copied a tutorial on Normal Maps. I made sure the Image Texture was using non-color data, but that didn't help at all. The texture appears to just create creases on the object now, and isn't really smooth at all.

Here is an image with a set of screen captures that depicts the issue fairly clearly.

https://i.stack.imgur.com/fPG8T.png

Any help would be greatly appreciated, thanks!

gandalf3
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user2446445
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    It looks like your normal map is working fine. However, you have horrible shading glitches. Note that the glitches are there without the normal map. Is your model set to smooth shading, and what is your light setup? – Ascalon Nov 03 '15 at 06:02
  • Oh, that makes a lot of sense. It is in fact set to smooth shading, and I just have one plane set up with emission to the upper right hand corner. It is as basic as I could make the scene. – user2446445 Nov 03 '15 at 06:11
  • Update: So I added in another light opposite of the other one, to test the shading further. It no longer has the artifacts that it had, but the model still looks very flat compared to the old one. i messed around with the normal map properties outside of the node editor and figured it out. I just have a lot to learn about shading I guess. Thanks so much for your help! Everything is great now! – user2446445 Nov 03 '15 at 06:35
  • @user2446445 also it looks like you have some inverted normals anyway. MAybe you could post your normal node set up, so we can make better suggestions. People often do normal maps differently in cycles with nodes. – Marten Zander Nov 03 '15 at 08:35
  • @Slim Marten How could I tell if the normals are flipped? They worked perfectly fine in Blender Render engine so I don't see how this is possible. My normal map node setup was definitely off, which was the problem. Current state: http://i.imgur.com/x8iF2Ja.png – user2446445 Nov 03 '15 at 10:11
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    This is likely due to terminator artifacts – gandalf3 Nov 03 '15 at 10:45
  • @gandalf Yes, I read about that, but this model is 2500 vertices, so it's not that low. It renders just fine now. It just needed a bit of tweaking. – user2446445 Nov 03 '15 at 19:31
  • Do you have activated option "Non Color Data" to Image Texture node (for the normal map) ? – LukeNukem Nov 04 '15 at 12:18
  • The OP said "I made sure the Image Texture was using non-color data but that didn't help at all". Also note that even if it wouldn't be activated, the problem would be with the strength of the effect, but not with flat-like faces. – Mr Zak Nov 04 '15 at 12:31

2 Answers2

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Terminator artifacts

As gandalf3 pointed out, you are suffering from terminator artifacts. I have seen this before in my own models, but didn't know that there is a name for it :-). This is one issue with normal mapping. Blender uses the normal map to calculate the final shading at a particular point on the model, but it can't use the normal map to determine whether or not the light is hitting part of the model. Blender only uses the physical model to calculate where the light hits. Normal maps are only a form of trickery used to make the model appear to be higher resolution than what they actually are; they don't really add new geometry.

The reason it didn't appear when you were using Blender internal is probably because the lighting was different (judging from the picture). You will have to either use subdivision to make the lighting calculations more accurate, or adjust your lighting so that the dark area is lit.

Community
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Lysol
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I believe the problem is with your faces. They are not attached together at the artefacts you see.

What you need to do is use the "remove duplicates" function. Enter edit mode, select all vertices, and press spacebar and search "remove duplicates" and run the operator. Keep the threshold low so you don't accidentally collapse some vertices.

Next all the normals have to be uniform. Select all verts and use the "Recalculate normals (outside)" function in a similar way to above.

This should fix some of your shading problems.

beiller
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