The sky is really blue

[jo99]

I was wondering if anybody would post a nice tutorial for sky replacement in nuke

[fxnurbs]

It changes on every case.
You can try to key/lumakey your sky, or roto it.
if your sky change dramaticaly, you would probably need a little glow on it to make the edges smoother in the light
always depend of the shot

you can find sky replace tuto for shake i am sure, the way to do it is very similar anyway