i need this complicated expression. any expert around here?

[Kevin Camp]

i would set it up differently…

It would be much simpler to use layer controls to select the countries. that would mean that all the countries would need to be in that comp, but you could make them shy layers to keep the comp simple (maybe even lock those layers to prevent accidental repositioning).

so in the comp that has all the countries, add and new solid. add 2 layer controls and the beam effect. then use an expression like this to link the start point:

target = effect(“Layer Control”)(“Layer”);
fromComp(target.toComp(target.anchorPoint))

and this to the end point:

target = effect(“Layer Control 2”)(“Layer”);
fromComp(target.toComp(target.anchorPoint))

now as you change the layer control the start and end points should move to the anchor points of those layers.

if you needed to add another line, simply duplicate the beam layer and choose new start and end point layers.

Kevin Camp
Art Director
KCPQ, KZJO & KRCW

[Filip Vandueren]

I second Kevin’s way of working.
If that’s not possible, (maybe you need those pre-comps because of certain effects) let us know and we’ll figure the other way out.
Shouldn’t be too hard, but the first thing I thought was indeed: layer selectors would be more elegant

[Constanti Dinu]

gentlemen,
first of all i want to thank you so much for your answers. there’s a good reason why i use this forum, and it’s because i learn new things. i started to deal a lot latelty with expressions, but i didn’t got the chance to find out about layer control until now.

yes, your sollution is very effective, and it’s kind of handy. and i didn’t check the project yet, but as i remember, i am able to move all the countries layers in the same comp. the only big problem about it is the fact that all the controls that i’ve managed to build in the project are in a single comp, so it would be very user-friendly. and the problem that this comp with all the controls, that acts like a control panel, it’s not the same comp with the countries. and unfortunatelly, you cannot link layer controls to other comps. so we must find another way about it.

kind regards,
Constantin

[Constanti Dinu]

doesn’t have to be a beam, the idea is to build a trajectory on the map that has a cc sphere on it.

[Filip Vandueren]

I’ve thought some more abpuot this. I think the expression is possible. But this is an impossible workflow to maintain.
There is absolutely no way to look at a comp you open and know from where to where the beam is keyframed at a certain position, apart from the result you see in the render-window if the expression works.
But what if the user sets half of your hundreds of layer-slider to “1” and the other half to “2” ?
The expression would take the first 1 and the first 2 and connect them… There is so much that can go wrong with small mistakes. And then you have to hunt down 200+ values on 6 layers…

What would you think of this solution: still not foolproof, but VERY handy workflow:
You create markers on your beam layer with comments like “Japan/South Africa” and the beam starts at Japan and ends in South Africa… Next keyframe is “South Africa/Belgium” etc.

It’s easy to make a typo, but it’s trivial to troubleshoot them… And very very clear in your timeline what’s going on.

[Filip Vandueren]

This expression works for me in the markerName scenario.

Note that both from and to get calculated, with very little more work you could use both these values in a linear() or ease() function to control the point of a “Write On”-effect.

v=value; // fallback value
err='';

splitString="/"; // change in case you don't want to use a slash

continents=[];
// link your precomps layers here!
continents[0]=thisComp.layer("afrika");
continents[1]=thisComp.layer("asia");
// continents[2]=thisComp.layer("europe");
// etcetera

m=thisComp.layer("beam controller").marker; // the layer where the markers are

if (m.numKeys) {
thisMarker=m.nearestKey(time);
if (thisMarker.time>time && thisMarker.index>1) { thisMarker=m.key(thisMarker.index-1); }
markerName=thisMarker.comment;
countries=markerName.split(splitString);

// find the countries in the precomp to get their position
if (countries.length>1) {
fromCountry=countries[0];
toCountry=countries[1];

// check contintentcomps for position
fromPos=false;
toPos=false;

for (i=0; i<=continents.length; i++) { try { fromPos=thisLayer.fromComp(continents[i].toComp(continents[i].source.layer(fromCountry).position.value)); } catch(e) {} try { toPos=thisLayer.fromComp(continents[i].toComp(continents[i].source.layer(toCountry).position.value)); } catch(e) {} } if (fromPos&&toPos) { v=fromPos; // or toPos ! this is where the layer get's set } else { err="didn't find " + fromCountry + " or "+toCountry+" in subcomps"; } } else { err='markername malformed'; } } else { err='no markers on layer'; } v;

[Constanti Dinu]

hey, i think i have the sollution:
how about i make a null in the “control panel” where i add the layer controls, copy all the countries layers in this comp, turn them invisible, and link their anchor points, to the original countries layers from the original comp? that way, i have layer controls where i want them, with the anchor information from another comp. what do you think?

[Constanti Dinu]

this is getting frustrating, is not working and i can’t tell why.
did is what i did.
in the main comps, i made nulls for every country, and parented the anchor point of the null to the country from another comp.

main comp europe comp
anchor point parent to
austria null ———————————–austria layer

main comp
trajectories null that contains:

layer control 1 – set on austria null
layer control 2
beam, with starting point expression
target = effect(“Layer Control”)(“Layer”);
fromComp(target.toComp(target.anchorPoint))

the expression is enabled and i got no error, the problem is it does not retrieving the true anchor point numbers from austria null. any thoughts?

[Constanti Dinu]

i did some tests, and it seems that the beam expression reads the original anchor point of the null, and not the numbers changed from the expression