Green screen masking issues

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jallen0

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Green screen masking issues

PostThu Sep 16, 2021 5:24 pm

OK, I'm lost. I looked at multiple videos and just cannot figure this out.

Setup: Green screen shot. This is a person standing center screen and on the left upper corner is a modifier that is in scene.

Goal: Remove the modifier by masking and then remove the green screen background

Steps: I have done this both ways and they both fail.
Node 1: Mask out the modifier using the pen tool in the power windows. The leaves the inside of the power window with just the person and the outside area black. I have created a Alpha Output and connected it.

Node 2: Add the 3D keyed to revoke the green screen inside the power window. Nothing happens and the green will not remove. Note that this works perfectly without adding the power window masking.

When I flip things I get the same result. I cannot figure out how to both mask the modifier out and key the green screen out.

Can someone point me in the right direction?
2019 MacPro OS 11.5.2, 3.2GHz 16 Core, 160GB Mem, 4TB Drive, 8TB Internal Sonnet Raid, Dual Radeon Pro W5700X 16GB
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xunile

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Re: Green screen masking issues

PostThu Sep 16, 2021 6:10 pm

Do you have it connected like in my example, one node for the Power Window with it inverted, and one node for the 3D Keyer also inverted?
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jallen0

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Re: Green screen masking issues

PostThu Sep 16, 2021 6:16 pm

Nope. I had the alpha channel from the first node go to the output and did not connect it to the second node and then send that to the output. Once I did that it worked. Thank you xunile!
2019 MacPro OS 11.5.2, 3.2GHz 16 Core, 160GB Mem, 4TB Drive, 8TB Internal Sonnet Raid, Dual Radeon Pro W5700X 16GB
LG UF 5k, 27" Tbolt Display, 55" LG C8
Resolve Edit Keyboard, Mini Panel, US 4K Mini
Resolve Studio Ver. 17.3.1
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xunile

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Re: Green screen masking issues

PostThu Sep 16, 2021 6:22 pm

You're welcome.
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Marc Wielage

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Re: Green screen masking issues

PostThu Sep 16, 2021 11:37 pm

I use garbage mattes all the time just on the possibility that the green screen isn't uniform, or there's a boom mic or cable that sneaks in from time to time. I think that's a good habit to get into. Garbage mattes are detailed in Chapter 135, "Secondary Windows and Tracking," starting on p. 2683. This is critical information (I started to say "key information," but that would be a pun) on how to pull off a good green screen. Mandatory reading.
marc wielage, csi • VP/color & workflow • chroma | hollywood
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jallen0

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Re: Green screen masking issues

PostFri Sep 17, 2021 12:00 am

Thanks Marc, I'll read that chapter.
2019 MacPro OS 11.5.2, 3.2GHz 16 Core, 160GB Mem, 4TB Drive, 8TB Internal Sonnet Raid, Dual Radeon Pro W5700X 16GB
LG UF 5k, 27" Tbolt Display, 55" LG C8
Resolve Edit Keyboard, Mini Panel, US 4K Mini
Resolve Studio Ver. 17.3.1
Desktop Video 12.1
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jallen0

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Re: Green screen masking issues

PostFri Sep 17, 2021 12:03 am

One last green screen question. is it common to set the screen at around 40 IRE and the talent at around 60 IRE? Are those hard and fast rules?
2019 MacPro OS 11.5.2, 3.2GHz 16 Core, 160GB Mem, 4TB Drive, 8TB Internal Sonnet Raid, Dual Radeon Pro W5700X 16GB
LG UF 5k, 27" Tbolt Display, 55" LG C8
Resolve Edit Keyboard, Mini Panel, US 4K Mini
Resolve Studio Ver. 17.3.1
Desktop Video 12.1

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