Can I use a matte clip as a holdout over another matte clip during a remove?

Hi guys

I’m trying to hold out some foreground objects (some power poles) from an imported matte clip layer (moving cars) for a remove.

I’m using a matte clip for the moving cars and I’ve then tried to use a matte clip as a holdout for occlusions above the ‘cars’ layer but when i go to render the remove, the resulting render seems to disregard the hold out matte layer at the top.

Can only splines be used to hold out shapes over a matte clip?

For context, here is part of the shot:

Here is a screen shot of my 3 layer set up for the remove:
3%20layers%20used%20in%20remove

here is my original plate with light poles and occlusions in front of the traffic

here is a test remove, where I have the holdout matte clip, the moving cars matte clip and the background tracking shape, but the occluding light poles are not held out… hence the parallax shift on the lightpoles etc muddies up the remove…

Just noting I’ve figured out the way I probably should have done this to begin with…

rather than attempting to minus the occluded objects matte clip during the remove render stage, I instead created a new clean file, ordered the ‘occlusions’ matte clip layer on top and the ‘moving cars’ matte clip layer at the bottom, changed the Blend mode of the ‘occlusion matte clip’ to ‘Subtract’. (it is set to ‘Add’ by default)…

Capture%20of%20subtracting%20occlusion%20matte%20from%20moving%20cars%20matte

I then selected File > Export Rendered Shapes to generate a single Matte Clip with the occluded light poles etc. punched out of the matte. Looking like this:

Capture%20of%20matte%20with%20occlusions%20punched%20out

then I simply used this all in one matte clip for the remove render.

Im going to take out the lightpoles in the clean plates where the remove is rendering so there are no blurry midground poles sneaking back in, then I’ll just insert new light poles back over the top of the rendered results.

You can use a black and white matte for removes, but there’s currently a bug happening with that workflow where the matte works but doesn’t visually update.

You can also simply over-remove the cars and poles together, and then composite them back over the top, and you might get better results that way too. But I am glad you found a solution that worked for you.

Cheers,
Mary

Thanks Mary
I’m going to clone out the light poles where they intersect with the freeway lanes from my clean plates and composite them back over after the remove as you suggest.

I’ve also come to realise vehicles can reflect a lot of subtle colour and light variations onto the ground and steel barriers that my roto shapes evolved from initially being quite tight around the cars to eventually being big rough garbage mattes so that I don’t miss any subtle colour and light changes occurring. I found that turning off illumination modelling was best for this shot, and using larger shapes around vehicles was best to completely remove any trace of traffic.

Thanks for all the tutorials you and the team produce, they are an invaluable resource!

Vehicles definitely have a lot of light and shadow play on the ground, I am glad you are using larger masks to compensate for that. I am glad the tutorials help you!

Cheers,
Mary

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