[Walter Soyka]

This expression, applied to the property with the keyframes that you want to loop, should do the trick. It will calculate the nearest number of complete cycles that will fit in the comp time based on your keyframe timing, then loop it like cycle from the start of the comp to the end.

Note that you will lose direct control of timing; it will stay as close as possible to your setup in order to loop seamlessly.

if (numKeys > 1) {
	var keyDuration = key(numKeys).time - key(1).time;
	var compDuration = thisComp.duration;
	var numCycles = Math.round(compDuration / keyDuration);
	var cycleDuration = compDuration / numCycles;
	var cycleTime = linear(time % cycleDuration, 0, cycleDuration, key(1).time, key(numKeys).time);
	valueAtTime(cycleTime);	
}
else value;

[Walter Soyka]

Once the camera passes your emitter in the scene, you can’t see the particles anymore — they’re emitting behind the camera now.

You either need to make the emitter larger (so it covers the entire range of your camera’s motion), or you need to move the emitter with the camera.

[Walter Soyka]

If you worked in 3D instead of 2D, you could animate the Z-position instead of worrying about the layer order. Moving something back or forward just 0.1 pixel in depth would be enough to change it from foreground to background, but not so much that it would noticeably change the size or positioning of the object in-frame.

[Walter Soyka]

Yes, I can think of two ways:

1. (Old-school, less flexible) Build your animation in one precomp so it animates from 0 to your maximum value, then duplicate that layer as many times as necessary in your main comp and use time remapping to individually animate them.

2. (New-school, more flexible) Use Ae’s new Essential Graphics workflow, which lets you build a precomp like a template once, publish specific properties (like the slider to control the size of the stack) and then re-use the one comp multiple times, as separate instances with separate values, elsewhere in your project.

This will make much more sense after you read through a couple of relevant links to get you started:

https://helpx.adobe.com/after-effects/using/creating-motion-graphics-templates.html

https://www.schoolofmotion.com/blog/essential-graphics-panel

[Walter Soyka]

Just to be sure you are both talking about the same thing — the Hide Shy Layers composition switch is Kilroy, the little guy with the big nose looking over a wall, and it’s up at the top of the timeline panel, above all the layers, just to the right of the timeline search box. This is different than the Video or Visibility layer switch (eyeball) or Solo layer switch (circle).

When that Hide Shy Layers composition switch is blue, that means the switch is active, and any layers with their individual shy switch enabled will be hidden from view in the timeline. Toggle that composition switch to reveal them. (You’ll also note thicker line dividers in the timeline panel when layers are shy, and you’ll see the layer index skipping numbers for the hidden layers.)

More here:
https://helpx.adobe.com/after-effects/using/layers.html#show_and_hide_layers_in_the_timeline_panel

[Walter Soyka]

You can’t apply effects across an entire label group the way you want, but you can use some built-in features to write the expressions that would link the properties for you.

On the first layer in your label group, add the effects you want. Then select those effects and Edit > Copy with Property Links. Next, select the OTHER layers in that label group and paste.

This will paste the effects, but instead of pasting with values or keyframes, they’ll paste with links back to the effect you copied. This will allow you to change ALL the values on the same group from the controls on the first layer in the group.

https://helpx.adobe.com/after-effects/using/edit-expressions.ug.html#link-expressions

[Walter Soyka]

Can you post a simplified AEP so we can take a look?

[Walter Soyka]

There are a few things that break 3D space / intersections / shadow-casting in Ae. Are any of these your culprit?

• 2D layers between 3D layers

• Adjustment layers

• A 3D precomposition layer without collapsed transformations

• A 3D precomposition layer to which an effect, closed mask (with mask mode other than None), or track matte has been applied

• A 3D layer with a layer style applied

Additionally, I think shadows are always turned off in Draft 3D mode.

[Walter Soyka]

You CAN have the instances work in Ae. It’s a game-changer. Easily the most important feature to hit Ae in the last 10 years, and it’s sadly kind of under the radar!

Set up your comp in Ae with the Essential Graphics panel. Then, when you use that comp as a layer in another comp, if you twirl it open in the timeline, you’ll see that you have access to “Essential Properties.” Everything you rigged up in the Essential Graphics panel is now accessible in your timeline on a per-instance basis, no True Comp Duplicator required.

[Walter Soyka]

FYI, the resizing method you’re describing here — adding a null, pickwhipping to it, and scaling the null down — is exactly how the “Scale Composition.jsx” script that ships with After Effects works.

I agree that working at 4K and scaling down at render would probably be the best course of action, especially versus backwards-engineering a complicated template system.

If your computer is struggling while you’re working, I’d suggest some performance tweaks like lowering the viewer resolution, turning off motion blur in the viewer, solo-ing just the layers you need, reducing the preview frame rate, using Draft 3D, using the region of interest, temporarily turning off effects on heavy layers, using proxies, etc.