Hasta La Motion!

I am very new to nuke and am begining to understand it more and more now.. I have learned couple of cool tricks that i wanna share.

1. Overlapping masks, color correction problem and fixing it.
If you have two masks that are overlapping and you get some strange results where they overlap than what you can do is connect those two beziers with merge node operation multiply – what that does is nearly connects both of them together and making whenever they overlap the one not to be shown.

Drop an a merge node, connect the A pipe to the bezier that should not be shown and connect the b pipe to the other bezier which will controll where the mask will be shown.. (set the operation to multipluy on the merge node.
Now whenever the bezier connected to the A pipe will be shown only where is overlapping with the other bezier that we connected to the B pipe
(if you need more explenation i will post some screenshots.)

2. Pulling the reflections on top of your elements.
Lets say you are working something on a eye and now all your added elements are covering the reflections of the eye which are big factor in the realism at the end..

What we can do is mask the eye where it have reflections, add a grade node and pull everything black in.. you may wanna play with the black point and white point of the grade node(you can as well add a colorcorrection) and pull everything in leaving the reflections only. Now put a merge node with operation (plus) over your elements connected with the grade… that will put the reflections on top of the elements however it will be too bright, now to fix that we can do the very same thing just reversing the operation.. add another merge (over) under the (plus) now add another merge (minus)connected with the grade and connect it with the merge over(over). be careful you need the A pipe from the merge (minus) connected to the original footage and the b pipe connected to the grade.. and now connect the merge (over with the minus pipe)
Done..
It;s pretty much complicated if you need more explenation tell me so i will post some screen shoots.

3. Color correcting with primatte if you need to preserve some colors.
So lets say you wanna keep the reds in the footage but wanna color correct everything else..
Ok select your footage drop in a primatte (make sure is connected to the fore ground) and with opperation set to Select BG color .. click the color pick up and select the color that you wanna preserve. now deselect everything and put in a color correct node.. connect it directly to the footage and now pull the mask node from the color correct node and connect it to directly to the footage… and look in the viewer trough the color correct.. and its done.. now you can color correct everything while preserving the color you masked out.

i need to go now, however i will post some more late.. and i ask you to do the same.

thanks

edit: i have posted in the wrong forum i think.. please move this thread to NUKE from The Foundry … sorry