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Mask question

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Scott GaskinMask question
by on Apr 25, 2014 at 2:38:52 pm

Hi,

Wondered if someone could help me.

Please see my attached image. If you look at the top window above the door there is a mask I created which is feathered to give the glow of light that I like the look of. I achieved this by creating a dark solid over my scene adding a ramp and multiplied to create a night scene. I then masked the solid over the window area which gave it this nice effect. The problem is Im having trouble creating the same effect over other windows in my scene. If I try this it just cancels the other mask out. Is there a way I can achieve this?

Hope This makes sense

Cheers

Scott



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George GoodmanRe: Mask question
by on Apr 25, 2014 at 3:45:46 pm

The problem is your ramp. You don't need it either. Just make a solid above everything that is black or blue or whatever you want your night color to be. Set it to multiply and adjust your opacity so that the parts that you want to look the darkest is to your liking. Now create multiples masks on that solid and use the feathering on each mask to create the gradient glow of the window.

There are a bunch of ways of doing this though, that is just the closest to what you're already doing.


"|_ (°_0) _|"

Sincerely,

George


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Scott GaskinRe: Mask question
by on Apr 25, 2014 at 10:46:01 pm

Thanks for your reply George. However I'm getting the same problem as before. If I create a second mask on the solid to create a glow on the next window it cancels the other one out. As soon as I invert the second mask I loose the original. Am I missing a step?

Many thanks

Scott


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Darby EdelenRe: Mask question
by on Apr 25, 2014 at 11:09:00 pm

Don't invert the masks. Instead set them to the Subtract mode.

If you want to be super diligent then you should first apply a layer sized rectangular mask to the layer set to Add, then create your Subtractive masks.

Darby Edelen


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Scott GaskinRe: Mask question
by on Apr 28, 2014 at 6:08:31 pm

Thanks Darby,

I worked it out by a bit of trial and error in the end! I'd be interested to know why I shouldn't invert the mask and why to create the layer mask first?

Many thanks

Scott


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Darby EdelenRe: Mask question
by on Apr 29, 2014 at 4:28:27 am

Think of the masks as alpha mattes with blend modes instead.

When you have a mask set to 'Add' and Invert it you are essentially telling AE "fill my alpha with white except inside this mask." As soon as you add another mask set to 'Add' and Invert it you will be filling every part of the alpha with white except where those two masks overlap (because that is the only area that is not being filled with white).

The 'Subtract' mode is preferable because it will always black out the alpha inside each mask.

The reason to add a layer sized 'Add' mask before using 'Subtract' masks is that there's a long standing unexpected behavior in AE when you reduce the mask opacity. Instead of the subtracted area becoming less subtracted, the area outside of the subtracted area becomes more subtracted. Unless, of course, you have a layer sized 'Add' mask above your 'Subtract' masks :)

Darby Edelen


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Scott GaskinRe: Mask question
by on May 1, 2014 at 9:25:10 pm

Thanks for the explanation Darby. Really appreciate it!

All the best

Scott


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George GoodmanRe: Mask question
by on Apr 28, 2014 at 1:09:33 pm

What Darby said. I didn't specify, but you should be using the subtract mode for all of those masks.


"|_ (°_0) _|"

Sincerely,

George


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Scott GaskinRe: Mask question
by on Apr 28, 2014 at 6:09:27 pm

Thanks for your help George

Scott


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