sorry for not being clear. no, replace won’t work here.
Let me explain more clearly.
Lets say I have 3 clips, CLIP A, CLIP B and CLIP C on a timeline.
CLIP A has a transition to CLIP B
CLIP B has a transition to CLIP C
additionally, CLIP B has 5 frames of head and 10 frames of tail.
Now, CLIP B is a rendered CG shot that I want to replace the content of the clip, but preserve the head (5 frames) and tails (10 frames) and also not change the transitions. Is there a way to do this.
Now if you are familiar with After Effects, this is the same functionality as option (or Alt on a PC) draging a new clip from the project window to a clip on the timeline you want to replace. the heads/tails and all attributes are preserved.
I do commercial work on a smoke usually and this is something I do 100 times a day and is pretty straight forward on the smoke, I am hoping it is even easier on FCP, forgive me for the long explanation.