Author Topic: Shader Error Including Alphas  (Read 74 times)

So after spending hours troubleshooting what could be the issue here, I've narrowed it down to the fact that this issue only shows itself when using a shader that includes alpha channels in some way. The issue is, as you can see below, that there is this one little square area on a piece of my mesh where one side seems to bleed to the other and vise versa. This is not on a single plane either, it is a strap with thickness. I have learned that the issue is not my texture maps. I originally discovered this problem via my AO map, as when it baked in Substance Painter and a little black square showed up on the front side of the backpack strap. I ended up removing said black square in photoshop and reimporting the texture, but the issue remained, but only when viewing "material" in the view port and not on the ao map by itself. Then I figured out the issue could be replicated using the base color map too. I also confirmed it wasn't my maps because the issue doesn't come up in Maya. After messing with the shaders in Substance Painter, I learned that it appears this issue only shows up when using a shader that deals with alphas in some way. I need to use a shader that has alphas on my other texture set, as it has single planes where both sides need to be seen. Luckily, I can use a different shader for this texture set, so I have an available work around for now. I'm hoping this issue doesn't appear anywhere else.

Any ideas on why this is happening though or how to truly fix it? Is it a bug? What could be the cause here? This isn't happening to the whole face either as you can see by the wireframe, it's just happening to one area on two separate faces.

Thanks in advance for any input!


This a is a know issue, our alpha blend shader may have face sorting issue sometimes. That's why we usually advise to split in a separate Texture Set the geometry that should be transparent.
Don't forget your log file. It can be exported from the Help menu of the software.
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Froyok aka Fabrice Piquet, Technical Artist and Product Designer at Allegorithmic.