Is there a subtraction mask tutorial for rotoscoping blades in After Effects?

I think this step is a very difficult one and it is currently the only one keeping me from finishing my video.

 

...what do you need to know? Removing parts of blades?

 

Yea basicly. To be more spacific I need to know what to do when a blade passes behind someone.

 

....no prob.

:::Typing a quick tutorial, refresh in a few minutes:::

 

I assume you are using Ryan's method for this, even though it doesn't really matter.


Once you have completed your first comp and are ready to start adding glows and stuff, stop. Discontinue. Halt.

Make a new comp, and import two things to it: your footage, and Comp 1 (The black-with-white-blade-shape-comp.)

Place Comp 1 over the footage in the layers queue, and set Compie's transfer mode to 'screen'. To do this, observe the following.

Your layer area should look something like this:

[@][i> Comp 1][/][][][][####################]
[@][i> Footage.mov][/][][][][################]


...or something like that.

Right-click on Comp 1, and go to Transfer Mode/Screen. This will make all black areas of the image transparent.

Click on 'Comp 1' once, then draw a mask for it. If you don't have the tools window out, go to Window/Tools and get it. Select the little pen looking icon, which is for masks. Make sure Comp 1 layer is selected, and click a four-six pointed mask (shape of lines) around where you want the blade to NOT be. Double click on the last point, you know, to finish of the shape.


DON'T FREAK!


I know your blade just disappeared everywhere BUT there, because it's still an additive mask. Twist the little triangle next to 'Comp 1' layer so you cascade the layer's window down, and then cascade in the same manner again. Select 'Masks' then 'Mask 1.' Then just change it's settings to a subtraction mask. From here you can just manipulate it like the blades masks from Ryan's tut.


Hope this helps. If you need any help, I'm sure there's some people online who'll throw some suggestions your way. But I'm hitting a movie, so, seeya.


Fig

 

well, you can do what figrin suggested (to be honest i got lost) or you can just make another mask (in the lightsabers layer) that conforms to the object in front of the saber, click the arrow next to that mask for its properties and click the little pull down list that presently says 'add' and select subtract.

That subtracts the lightsaber from that masks area, in effect making the object appear to be in front of it. You will most likely have to animate the mask to conform to the object in front of the saber. Then you duplicate the saber layer for the glow and continue with the process.

 

I do have a section on subtraction masks in my text tutorial pages. It's in Part I and titled Handling Obscurities. If there's something that I didn't make clear, let me know.

 

Yea i still have a question. Should I rotoscope the whole piece of video and then add in the subtraction mask, or should i do it together?

 

Rotoscope the sabers first, I'd create a new mask and change it to "subtract" just before I would add the color to the glow.

 

Is adding a mask the same as a layer?

 

No. The different masks are working on the same layer in differnt fashions. Add masks will reveal parts of that layer while Subtract masks will make that part of the layer transparent.

 

Ryan - it looks like your heading on obscuraties could have beena little clearer....

Pete

(I found it funny anyway)

 

My method:

Mask the saber with keyframes. Instead of subtraction masks.... paint black with the vector paint thing, and use it as your saber core alpha.... well, actually, I haven't tried it yet, but I will soon. I imagine it'd work perfectly fine.

 

Ok i think i got it.