Some of the trees leaves have issues with transparency, why is this?
The material settings:
Image (by Krzysztof P. Jasiutowicz, source :
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By looking at your render, I would check for doubled up leafs, as in z fighting. – David Dec 13 '14 at 18:01
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@David the incomplete transparency shows a quadrangle shape this shouldn't be z-fighting. Added the edited image (original was JPEG without transparency) – stacker Dec 13 '14 at 18:17
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The Alpha value might not be 1... – someonewithpc Dec 13 '14 at 18:27
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@someonewithpc, close to 1 but not exactly 1 was it (fumbled too much on the node settings) – stacker Dec 13 '14 at 18:51
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@David z-fighting made also sense for overlapped leaves from particle system. After I changed the emission from verts to faces the issue disappeared. – stacker Dec 13 '14 at 18:53
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@NoviceInDisguise As it currently appears, yes. Who is going to answer the question? Should probably have been two separate questions. – stacker Dec 13 '14 at 18:54
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@David yes you were first – stacker Dec 13 '14 at 19:06
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@someonewithpc. could you add the 2nd part as an additional answer? – stacker Dec 13 '14 at 19:07
2 Answers
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For this particular problem it seams like your shader, and image's alpha are not the problem, but rather z-fighting. When there are doubled up faces with transparency the z-fighting will not have the characteristic black look, but rather strange transparency artifacts (much like your render).
To fix the doubled faces, check your particle settings to see if there any duplicated leaves. If there are more particles then places to emit them, then they will get doubled up.
Here is a cube with 8 vertices, the particle system number for both is set to 32. The only difference in the two is for cube on the right I gave the particles some randomness.
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It seems like the problem is that the Alpha channel of your image is not 1; This leads to some translucency sneaking through where it shouldn't. To fix this, you can use many methods, but, probably the best is to use a Brightness/Contrast node:
If you put that node between your image's alpha and the Mix node, and set the contrast to a rather big value, such as five, the problem should be fixed.
someonewithpc
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2In cases such as this I find it cleaner to use a math node set to something like greater than. That way the output is clamped to 0-1, and you have an easy way to control the threshold precisely. – gandalf3 Dec 13 '14 at 20:25
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