[xavier loebl] "what if you want to apply it to a 3D layer that you have moved and rotated ? Right now i don't get it, can you apply it through a 2D blur layer that fits the main comp or do you need to apply it through a 3D layer with the same "geometry" as the 3D layer you want to get blurred ?"
i assume that you are asking about compound blur... you would apply compound blur directly to the 3d layer. it will use a gradient map that is a 2d layer (actually it can be a 3d layer, but it will only look at it as a 2d plane and map that to the plane of the 3d layer).
in ae, every layer is really a 2d object, but those objects can be placed in 3d space. all effects are 2d and are applied to 2d layers. some take a 2d layer and make it 3d, like cc cylinder, but that cylinder is only 3d within that plugin's space... meaning it won't be in ae's 3d space, so if you have other 3d layers that should be behind or in front of the cylinder, they will need to be bellow or above the cc cylinder layer because the cylinder is contained (or 'trapped') in a 2d layer.
it's a little confusing, just remember, ae is really a 2d system that can put 2d elements in 3d space, but any effect on those 2d layers are 2d effects even if the 2d layer is in 3d space.
[xavier loebl] "is there a means to apply any effect through a grayscale map, where black means effect off and white 100% effect on ?"
not any effect... only a few effects are 'compound' effects, meaning they can use data from one layer and apply it to another in some way. some simple ones are compound blur and displacement map, but others, like card dance, particle playground, foam and time displacement can use layer maps to create complicated animations.
to demonstrate, create a new comp, then new layer and add the wave world effect and set it's view property to height map. this just creates a grayscale wave animation, like a water drop, we'll use that to drive position of a bunch a tiles.
now, take that comp into a new comp and hide it. add a new layer and add card dance. set the rows and columns to about 50, set gradient layer 1 to the wave world comp you created earlier and set the z-position source to 'intensity 1'. add a comp camera and use the orbit tool to rotate around the scene to see the card dance layer as plane in 3d space. then ram preview....
it's a pretty complex animation for about 1-2 minute's worth of work and you can see how powerful compound effects can be.
there are a few tutorials on
ayatoweb.com (examples 21, 26, 49, 50, maybe a few others) that use compound effects to create animations if you want to learn more about them.
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW
