Polygon turn to black at rendering.. sometimes.

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Hello,

I'm using karma.
I have some polygon that appear black on final image rendering.
But on rerendering same frame all is good. It's not constant.




Do you already experience this kind of problem ?
Does-it have some king of thing to avoid ?
Is there some topology to avoid (triangle only needed ??).

Thank you,
Julien

Attachments:
black_square_on_polygon.png (572.7 KB)

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Any chance you could submit a hip file that demonstrates the issue? You can email support@sidefx.com if you're okay sharing the hip file with SideFX but don't want to post it publicly.

On a given hip file/frame/geometry does this happen consistently (i.e. the same polygon is black every time you do a render)? Or does it happen randomly (the same render done multiple times, the black polygon only shows up sometimes)?

Any additional info would be appreciated because at first glance this looks very bug-like...
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Hello,

Ok I go on rendering phase this weekend so I'll have probably more info about this "bug ?" recurrence soon and tell you.

For more info I rendering a big ground map composed of 107 textures of 8192 square pixels.
I'm using karma xpu.

I also notice on other frame a similar problem where small polygons and very few (2/4 primitives) don't turn black but dark like with a normal bug.
Once rerendered they became a bit more corrupted (8/9 primitives), then I triangulated and problem is gone(I hope).

I have heavy assets (like textures) but I can share you soon for more investigation.
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Bug replicated on "simplified" scene (still need all textures).
Mail already sended to suppport.
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ometimes when I render, there will be large areas of red, or a certain part of the smoke is missing, or black dots and black spots will appear.:/
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Months later I had the response, I use a cache by settings env variable for textures but this cache was not large enough.
You can read the post here for more info : https://www.sidefx.com/forum/topic/99657/ [www.sidefx.com]

In brief, if you want to use local cache to not overload your network, and want enough space, you can set it in json package like this :
"HOUDINI_TEXTURE_DISK_CACHE" : "temp size=409600"
It say to use the system location cache and allow 400Gb of space for this.
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