Diagonal barn doors wipe

[Guest]

I have a shot where train doors open, and I want them to open to reveal a title inside the carriage. Usually I would crop the left and right sides on the same clip, or I could even use the "barn doors" video transition effect.

However, the train doors are slightly diagonal.

How can I do this? Please please put your description in layman's terms for me, and any other newbies.

Thanks!

[gerikp · Accepted solution]

I would probably start with just adding a 4-point polygon mask to the title (In the Effects Controls Panel It's the rectangle right below your text). Then I would keyframe the corners to match the train doors opening.