Ben Rollason
2
AE Expressions Coins
2
COW Coins
Forum Replies Created
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you need to use valueAtTime()
For instance:-
thisComp.layer("matte_layer").position.valueAtTime(time - 3);will give you matte_layer’s position 3 seconds ago.
thisComp.layer("matte_layer").position.valueAtTime(time - (3*thisComp.frameDuration));
will give you matte_layer’s position 3 frames ago.thisComp.layer("matte_layer").position.valueAtTime(time + Math.sin(time*5)/2);will follow matte_layer’s position, but oscillating back and forth along the path.
-Ben.
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Found it!…
This script from Lloyd Alvarez’s page aescripts.com does what you want, I think.
https://aescripts.com/project-name-stamp-info-stamp/
– Ben.
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As far as I’m aware, no.
You can do it with scripts, but not expressions.
-Ben.
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Difference isn’t quite subtract. it’s an absolute subtract. i.e. it only gives positive values. if you subtract white from black, it should give negative 255, or 0 if clipped. Difference doesn’t do this – it gives the absolute value of negative 255 – i.e. 255 or white.
So white subtract black is white, whereas black subtract white is black (or -255 super black if you’re working in floating point). If we were using difference, they’re both white.
Here’s a workaround to get a true subtract:-
******** thisLayer subtract layer X ********
effect: Compound Arithmetic
(set second source layer to layer X; set Operator to Subtract; set Operate on Channels to RGB; set Overflow Behavior to Clip; set Blend with Original to 0%)You must make sure that the layer you are subtracting has a solid alpha channel – subtract does not observe alpha, but uses the pre-divided RGB values. If this second layer has an alpha, use a Channel -> Solid Composite over black effect, then precompose before applying the Compound arithmetic to the first layer.
______________________________________******** thisLayer subtracted from layer X ********
effect1: Compound Arithmetic
(set second source to the layer you are subtracting this one from; set Operator to Copy, Channels to RGB, Overflow Behavior to Clip, Blend with original to 0)effect2: Compound Arithmetic
(set second source to this layer, set operator to subtract, set channels to RGB, set overflow behavior to clip and blend to 0)______________________________________
As above: You must make sure that the layer you are subtracting has a solid alpha channel – subtract does not observe alpha, but uses the pre-divided RGB values. If this second layer has an alpha, use a Channel -> Solid Composite over black effect, then precompose before applying the Compound arithmetic to the first layer.
For all of these, do what you like with Stretch second layer to fit, but I prefer to have both layers the same size in the first place!
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Very curious. This sounds like a formats thing. What format are you rendering out?
For starters, I’d recommend that you export both versions as a Lossless Quicktime and see if they differ. If they don’t, then probably whichever format you are using only likes certain pixel dimensions?? mpeg?
I can’t say I’ve ever seen pixel size affecting gamma or levels though, although gamma is a thorny subject.
-Ben.
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Check that After Effects is interpreting the footage at the right frame rate.
Click on the imported footage in the project window and hit Ctrl-F (PC) or command-F (Mac). This brings up the interpretation dialogue box. Make sure that this frame rate is the same as the frame rate of your composition and the frame rate that you are exporting at.
If you had rendered in fields, then it could be that they were being interpreted the wrong way up, but you’d only notice this on a broadcast monitor or if you slowed the footage down.
If you exported from 3D as full frames, that shouldn’t make the footage jerky.
-Ben.
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Check here… these are brands without homes for sale as a package.
If you got in touch with some of the authors and asked if you could animate something with their logos, then maybe it could even be included as part of the brand!
-Ben.
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If you made the spiral a 3D helix instead, then if placed correctly, it would look like a spiral to the camera. The fishes would get smaller as they move away from the camera – due to perspective, but the distance between them wouldn’t change.
Otherwise you’ve got a nasty bit of expressions work on your hands, or a lot of manual tweaking.
There’s plenty of tutorials about getting things to follow 3D paths in After Effects.
One way would be to attach each fish to a null. Then rotate the null around its z-axis while at the same time moving it away from the camera along its z-axis. Then duplicate this arrangement up x times and offet them along the time line to get the desired distance.
-Ben.
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Yes, but you’ll be using some pretty advanced tracking, rotoscoping and painting techniques. What’s more, you need to make sure that you shoot appropriate plates (empty shots) to replace the holes in your footage.
This is a big subject.
In terms of software, you might find that Shake or Nuke is more appropriate to what you want to do. After Effects is a pretty good compositor, but these other two apps are built for it and nothing else.
– Ben.
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It’s irrelevant. A 72dpi image and a 300 dpi image will be exactly the same, given that their pixel dimensions are the same. You can test this. Save off a tiff or whatever of an image, one at 300ppi and one at 72ppi, making sure that their pixel dimensions stay the same (Photoshop will try and change them as you change the ppi in image size). Then import both into After Effects. Lay them one on top of the other in the same composition and set the top one’s blend mode to difference. Move the cursor over it and notice in info that all pixels are black. That means there is no difference.
dpi is actually to do with a printers resolution anyway. ppi is the equivalent referring to a screen’s size or resolution. Photoshop uses ppi relative to the documents intended print resolution in inches.
Inches has nothing to do with it. Just make sure you have enough pixels! 🙂
-Ben.