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| Forget the obscuration layer, you need to create and use a Z depth map. I do this a fair bit with particular within AE. There are 2 ways - you can buy a plugin (which is accurate but very slow) or you can use an expression, which is fast and free but a bit of a pain and not always 100% perfect (because the corners of a layer are a different distance to camera than the centre). To do it in AE, you need to duplicate your main composition with all your 3D layers and make a Z-depth version. Strip out everything that isn't a 3D layer and isn't going to interact with the ribbon. Add the fill effect to each layer, apply an expression to the colour to fill it with a shade of grey based on the distance to the camera: camp=thisComp.layer("Camera 1").toWorld([0,0,0]); // camera position // lp=thisLayer.toWorld(thisLayer.anchorPoint); // layer position // d=length(camp,lp); // distance from camera to layer // min=0; // this this number for white in particular // max=20000; // use this number for black in particular // v=linear(d,min,max,1,0); // convert distance to value 0 - 1 // [v,v,v,1] To keep things speedy I would pre-render the z depth map, import it and use it with particular -use the same camera distance value in particular as the min and max values in the expression. -Chris -----Original Message----- From: Teddy Gage [mailto:teddygage@gmail.com] Sent: Friday, February 21, 2014 10:58 AM To: 'After Effects Mail List' Subject: [AE] 3D ribbon with Particular So I am working for a fashion brand asking for a 3D ribbon effect that twists through fields of photos and video, going in front of and behind the images. My first thought was 3D stroke, but it didn't work, as I need it to have some shading from the comp lights. There's also the issue of painfully retiming the stroke moves using percentages of completion, and not actually having full "3D" control. (I can't draw a path that goes in all dimensions, just postcard transforms on the 2D mask paths, AFAIK.) I may however use it for some simple bending and repeating elements. My next idea is to use a particular 2.0 layer with 0 emit velocity, and having the emitter tied to a null that I can then fully animate through 3D space. So far this is working pretty well. Comp lights work, it is easy to control. However I am having some of the classic issues with Particular where it crosses other 3D objects in the scene and doesn't respect the stacking order. The ribbon is either completely in front of or completely behind the images. - now I could add 1 or 2 "obscuration layers" but it is not reasonable to do this for over a hundred layers individually - Would I need to precomp the entire layout, collapse transformations, and THEN use the precomp as an obscuring layer? Is this even possible? It would be a difficult way to work, I'd need to have every element layed out in 3D first. Doable, but I'd prefer to create both at once. - is there another solution I'm not thinking of? A good script for Particular maybe? Thanks, -TG -- _____________________________ VFX & Motion Graphic Artist teddygage dot com |
