[Bryan Woods]

Dan showed me that the easiest way to set an expression, get its result, then remove the expression is very simply: Set expression, put result into a new variable, then set expression to blank (easiest way to remove the expression is to just over write it with nothing!). I’ve used this for a script with sampleImage where I needed to offset the anchor point based on the alpha of the image. It moves the anchor point, then removes the expression so you’re not constantly recalculating.

See this thread:
https://forums.creativecow.net/thread/227/22776

[Bryan Woods]

I could have sworn I’ve seen it done before. Some kind of multi effect from a script I used a long time ago plucked from AEscripts. I thought maybe plexus did this, but I just checked and all the effects palettes are open when they’re created. I also checked the CS6 expressions guide pdf and no mention of anything like that in there. I can’t believe they wouldn’t put an option to set the state of the twirl down gizmo… 🙁 Maybe Todd would know?

By the way, thank you yet again for all your help. I really do appreciate all the effort you put into helping me and so many others on this forum.

[Bryan Woods]

Thanks Dan. That’s what I was missing; (“Effects”). Forgot that everything was in a master sub menu.

On a different topic, would you happen to know how to set an effect’s window to be closed instead of twirlled open in the effects window? This script is adding an effect and some sliders, and I don’t want the effect to be open (because it takes up a lot of space visually). I’ve seen others do it, but I have no clue how to access that kind of attribute. I’m sure its some boole operation, but I have no idea what the syntax would be for it.

[Bryan Woods]

Ah, that is a bit nicer. I’ll take that into consideration.

Another issue I’m having maybe you can point out the issue. I’m trying to roll this into a script, and I’m having a hard time targeting the “Output Black” sub property of the levels control. At line 23 I get an error stating “Null is not an object”.

//Set Undo Group

{
app.beginUndoGroup("SlideShow_FX");

//Define project and active items
var proj = app.project;
var theComp = proj.activeItem;
var selectedLayers = theComp.selectedLayers;

//For every layer selected...
for (var i = 0; i < selectedLayers.length; i++) {
var myLayer = selectedLayers[i];
var levelsAdjust = myLayer.Effects.addProperty("Levels (Individual Controls)");
myLayer.property("Levels (Individual Controls)")("Output Black").expression = "1"; //value of 1 is acting as debug. I'll put the actual expression in later
}
app.endUndoGroup();

}

[Bryan Woods]

Nevermind! Figured it out! Code below for any future reference:

Apply to Ouput Black on Levels effect (individual controls version):

//Autofade: Add to opacity

transition = 20; // transition time in frames

if (marker.numKeys<2){
tSecs = transition / ( 1 / thisComp.frameDuration); // convert to seconds
linear(time, inPoint, inPoint + tSecs, -1, -2.5) + linear(time, outPoint - tSecs, outPoint, 2.5, 4)
}else{
linear(time, inPoint, marker.key(1).time, -1, -2.5) + linear(time, marker.key(2).time, outPoint, 2.5, 4)
}


[Bryan Woods]

But its such a pain to do that. It kills the dynamic usefulness of the expression.

Would you happen to know of a way to convert the expression to keyframes, but only make one keyframe and not 1 for every frame? Because that ends up taking the most time when baking. I never need more than one keyframe usually when baking, and would probably speed things up greatly…

[Bryan Woods]

My background: Camera man > Film editor > Compositor (keying and finishing) > Motion Graphics Artist.

What I’ve learned:
Never do compositing (roto/keying/3D comping) in AE, and never do motion graphics in Nuke. Use the right tool for the job. AE == Nuke in terms of “high end” tools. If I have someone wanting to join my team for motion graphics and all he knows is nuke, I’d laugh at him. If I have a green screen shot that needs keying and my artist wants to use AE I’d laugh at him too! Your post is the equivalent of saying “I’ve been using acrylic paints for years, but I think its time I stepped up to the high profile tools, like Oils”.

Learn a new tool; be that much more valuable to a potential client/house. Its as simple as that. (and have fun).

[Bryan Woods]

Thats a really useful expression from that tutorial. Watch your speakers and ears though if you watch it. The guy has his mic up REALLY loud. I blew out my little earphones when I first started it. Pissed me off a good deal too.

[Bryan Woods]

Yup, what Dan said. I’d use the wiggle expression with a slider on a null object.

Create a null object, then add the effect “expression slider”.
Then go to the rotation property and put in this expression:
wiggle(1,slider);

The first value of wiggle is the frequency. 1 would mean “do this every 1 second”. The second value is the amplitude. Usually, you’d put a number in here, but if you want to be able to keyframe your wiggle, then you should pickwhip that null you created with the slider control for this value instead. Now you can keyframe the slider. 0 = no wiggle.

So, assuming your null is unnamed, your expression would look something like:
wiggle(1,thisComp.layer("Null 1").effect("Slider Control")("Slider"));

Adjust the first value to speed up or slow down the frequency of your wiggle and this should get you the result you’re looking for.

[Bryan Woods]

Ah so .value can contain an array without indicating what it should be. I was under the impression you had to separate it out. Thanks for the suggestion!