Expression and Masking

[Darby Edelen]

If you pre-compose the curtain and make sure that there is transparent space around the curtain layer (easiest way might be scale it down 5%) in the pre-comp the displacement map should displace the ‘edges’ of the curtain.

[Adolfo Rozenfeld]

You can’t apply wiggle() to a mask path, because the nodes’ locations aren’t exposed to expressions.

In CS3 you’ll be able to apply the Wiggle Paths operator (sounds pretty good, doesn’t it?) to a bezier shape path, which is identical and compatible with mask paths.

Adolfo Rozenfeld
Buenos Aires – Argentina
https://www.adolforozenfeld.com
adolfo(AT)adolforozenfeld.com

[Brad Strickman]

I attempted scaling and precomposing and the same problem exists. The bottom edge of the curtain remains static. Any other ideas?

[Darby Edelen]

[bdstric] “I attempted scaling and precomposing and the same problem exists. The bottom edge of the curtain remains static. Any other ideas?”

Nope, but I still have the same idea =)

You go the order wrong there, pre-comp and then scale inside that pre-comp… The goal is to make a layer (a pre-comp) that has your curtain solid in it but with a buffer of at least 20 pixels of transparency surrounding it. So if your curtain layer is 720×480 and your displacement is 720×480, pre-comp your curtain layer into a 720×480 composition then scale it down so that the curtain layer is about 700×460 inside a 720×480 comp. Then the displacement map will displace the entire 720×480 pre-comp. You’ll still have ‘hard edges’ but those ‘hard edges’ will be on the transparent pixels at the border of the 720×480 pre-comp (so you won’t see any hard edges).

Note that the 20 pixel buffer I mention here is pretty arbitrary, it really depends on your maximum displacement values in the displacement map effect. A 20 pixel buffer would work for a maximum displacement of up to 20.

[Ronaldo]

This may not be very helpful to you but Cinema 4D has a great was to do this. If you have access to it, let me know and I’ll fill you in.
All the best.

All the best

[Mike Clasby]

You can wiggle a mask’s verticies with expressions, it’s a little round about, see this:

https://forums.creativecow.net/cgi-bin/new_read_post.cgi?forumid=2&postid=897730

[Adolfo Rozenfeld]

Expressions can’t access mask nodes directly. Scripting can, as the link you mention shows.

Adolfo Rozenfeld
Buenos Aires – Argentina
https://www.adolforozenfeld.com
adolfo(AT)adolforozenfeld.com

[Mike Clasby]

And an excellent script it is too.

[Adolfo Rozenfeld]

True 🙂

Adolfo Rozenfeld
Buenos Aires – Argentina
https://www.adolforozenfeld.com
adolfo(AT)adolforozenfeld.com

[Brad Strickman]

Thanks for clarifying. It looks really good.