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How do you avoid negative RGBA values with matte control?

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joemart

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How do you avoid negative RGBA values with matte control?

PostTue Oct 04, 2022 4:09 pm

I'm substracting a polygon with another and the Alpha value seems to go below 0. How do I avoid this? Is there a way to default it to 0 if it goes below 0? How would I go about this?
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Sander de Regt

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Re: How do you avoid negative RGBA values with matte control

PostTue Oct 04, 2022 4:18 pm

How are you substracting them? What method are you using?
Sander de Regt

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Chad Capeland

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Re: How do you avoid negative RGBA values with matte control

PostTue Oct 04, 2022 5:25 pm

You don't need MatteControl to subtract a mask. The masks themselves have a paint mode.
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bentheanimator

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Re: How do you avoid negative RGBA values with matte control

PostTue Oct 04, 2022 7:13 pm

They're both right but if you need to floor a channel you can always add a Brightness and Contrast node. There's a check box for Clip Black and White. That will 0.0 black and stop White at 1.0.
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Bryan Ray

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Re: How do you avoid negative RGBA values with matte control

PostTue Oct 04, 2022 8:20 pm

Remember to tick the Alpha box if you need to clamp the alpha, though. BrightnessContrast has that unchecked by default.
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