[Thehardmenpath]

I have watched the video carefuly and I believe this has been done that way:
After designing the main graphic (just the yellow line) it was separated in different objects for each line or group of lines and uncovered with masks. I can see it in some curves where the yellow appears as uncovered by a line, not a vector paint progress. Check out the lowest yellow line in the r of poetry, for example. Separating it into layers allow to change colors and moving words as they do, and blik.

All this got then probably precomposed and the effect of drop shadow was added. By the way, if you want to add several drop shadows as they did, I recomend to start with a distance of one and increase it exponentially after that, starting with 2 in the second effect, 2,4,8,16.

I presume they did something BEFORE that, they put another drop shadow with the same properties but in the opposite direction to end covering the yellow part with a full stroke line. I think
the best way to keep everything in control is with expressions, so you only have to animate the values at the first effect.

Finally, check out a little mistake (or is it?) there: Parts that are not onscreen don’t project shadows, like the line that goes over the “h” of “they” at the end. Just like the drop shadow effect does.

[Thehardmenpath]

You seem to try to become a guru without becoming a guru, or at least, try to approach the matter in a very strange way.

How to master the programs? From my point of view, you have to think of something you don’t know how to do, that could even be impossible, and then see if you can or not. After a series of successes and failures you’ll probably have a good knowledge of what you can achieve with them.

[Thehardmenpath]

My English is terrible, so let me see if I understand: You have achieved to make a layer transparent through a luma. And you want to fade in a new layer BUT the transparent parts of the luma make them visible beneath the first layer.

My first choice: Can you put that new layer ABOVE the other ones and just change it’s transparecy?

Second choice: If it has to be below, you could use the same luma layer for the layer that fades in. And you could animate the brightness of the luma layer so that the transparent parts become opaque while the layer is fading.

I hope you understand what I mean, if the first layer is transparent, make transparency the same in the second one.

[Thehardmenpath]

That looks really hard to make in AE, certainly.

If I were you, I would rather try to do something else that probably suits much better in After Effects: Look for real floodings and replace the buildings.