How can i mask several layers without masking seperately?

[Sciencio5EC6]

I initally wanted to mask half the body to change exposure to make a shadow, but how can i get adjustment layer to work for certain parts of layers?

[RobShultz]

You can write several masks on one adjustment layer. You can also have the adjustment layer only above the layers that you want the masks applied to in the timeline. I'm not sure I understand your question but I hope that this helps.

[Sciencio5EC6]

Sorry for my bad English. I wanted to have some layers to get exposure by my adjustment layer, so is it possible I can use the whip tool to connect the adjustment layer exposure to the layers that I wanted to get exposure?

[Mylenium]

You cannot exclude layers from adjustments when they are below in the stack. You have to restructure your project by separating the individual layer sets in pre-compositions. I suggest you actualyl read the online help on such basics.

Mylenium

[Sciencio5EC6]

I tried to pre comp each body parts into one. The shoes disappear and the arm and stil size increased, why does this happen

[Sciencio5EC6]

Is it possible i can make specific layer have mask and exposure without having to do it seperately? 

Because i wanted to have a layer which i can control specific layer and exposure

[ShiveringCactus]

I imagine your precomps seemed like they disappeared because the layers are either off to the side or behind something and you just need to adjust their position.  

Does you comp have a background layer?  These will be affected by an adjustment layer too, but if you pre-comp your figure so that it is all one layer, you could use this twice, once underneath the adjustment layer and once as a track matte for the adjustment layer.  You'd then be free to add masks to the adjustment layer and they would only apply to the figure and not the background.

[Sciencio5EC6]

 I've learnt my lesson... I should precomp once I started my project... I have a background now it's impossible to make shadows of my character...

[ShiveringCactus]

Can you not take your comp, nest that in a new comp?  You can then treat this like a pre-comp, if you move the background and adjustment layers out.

[Sciencio5EC6]

Oh I precomp my comp, take out the background, so like that I can just mask adjustment layer without affecting the outside one? How can I make a pre comp a comp actually?

[ShiveringCactus]

All you need to do is drag your comp from the project panel into the timeline of another comp or at the bottom of the project panel there is the Create a New Composition button.  Drag your comp onto that to create a new comp with this one inside.

[Sciencio5EC6]

Err. Is it possible my layer can parent something outside of the pre comp? Because I have to bring the master null into my pre comp. But the background is also following the *master null*. Sorry for the late reply

[Roland Kahlenberg]

Effects have a Mask Reference feature which allows you to have an effect work within one or more Masks.

More info here - https://helpx.adobe.com/after-effects/using/mask-reference.html