Fading masks

[JCook]

I have an image I'm using as a scrolling texture inside a shape, and I needed to mask it, but have the mask change size and shape in such a way that I couldn't really use point animation easily, and I stumbled on this trick.

You can put into a masked group, several masking layers, at the bottom of the hierarchy. Set them all to mask normally the way you would with only one mask, and only the topmost mask will be active. You can then make the topmost mask disappear using the visibility or opacity (fading it out), and then the next mask becomes effective, and so on. I tried it with three masks, using both ways and it works like a charm. I haven't tried it using switch layers, but that may also work.

I thought I'd pass this along.

Jack

[jahnocli]

Good to know - thanks for sharing! It occurs to me that, if used cleverly, it could simulate movement with relatively little effort (well, less than normal, anyway!...)

[synthsin75]

Sounds good, I'd love to see an example.

[JCook]

I've put of couple of my test movies up on my ftp site. I've never posted movies here before and I don't know if there's a better way to do it, but here are the urls for the two movies. You should be able to view them without having to download them.



ftp://ftp.whoi.edu/pub/graphics/jcook/M ... hTest2.mov


ftp://ftp.whoi.edu/pub/graphics/jcook/M ... hTest3.mov

The first one was done using the visibility checkbox in the layer dialog. All the mask layers were visible at the same time, but the topmost one was active. When it became invisible the next one down took over. It's the same with the second movie except that I used the visibility channel to fade the masks out instead of having them disappear suddenly. I used particles for these tests, but in the final animation I'm using a scrolling image, and it works fine for that, too.

I didn't try this with switch layers yet, but I'm thinking that could work also.

Jack

[JCook]

I've just tried this using a switch layer and it works great. I put the three masking layers into the switch layer, removed the masking from them (checked the Mask this Layer button in each), and made the Switch layer the mask. Then just choose your mask from the Switch layer at the appropriate time. Here are two movies using this. Number 4 is just like using the visibility checkbox, the mask changes abruptly. Number 5 uses the Interpolate sub-layers checkbox in the Switch dialog, and the mask moves from one to the other, rather than changing abruptly or fading.

ftp://ftp.whoi.edu/pub/graphics/jcook/M ... hTest4.mov

ftp://ftp.whoi.edu/pub/graphics/jcook/M ... hTest5.mov

Jack

[synthsin75]

Nice. I like that interpolated switch layer mask. Sounds like much more fun than visibilty.